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Dissertations / Theses on the topic 'Plastic optical fiber'
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1
Polley, Arup. "High performance multimode fiber systems a comprehensive approach /." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/31699.
Full textAbstract:
Thesis (Ph.D)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009.<br>Committee Chair: Ralph, Stephen; Committee Member: Barry, John; Committee Member: Chang, G. K.; Committee Member: Cressler, John D.; Committee Member: Trebino. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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CASALICCHIO, MARIA LUISA. "Innovative Plastic Optical Fiber Sensors." Doctoral thesis, Politecnico di Torino, 2012. http://hdl.handle.net/11583/2497120.
Full textAbstract:
This thesis describes the development of new types of fiber optic sensors for the measurement of
mechanical quantities such as displacement, vibration and acceleration.
Also, it describes the realization of specific acquisition systems designed to interrogate the developed
sensors.
Since optical fibers have been historically associated with high speed telecommunication links
because of their very large bandwidth and low attenuation, there is a great interest for their employment
in sensor applications.
Fiber sensors represent a promising solution in many fields since fibers can be used for the measurement
of several quantities, not only mechanical as those investigated in this work, but also
chemical with the possibility to detect specific chemical or bio-chemical molecules.
Among the physical quantities to be detected, the displacement measurement is required in some
applications, especially in structural civil and mechanical fields, where it is possible to evaluate
the cracks evolution, providing information about the safety of the structure under monitoring in
order to detect eventually risky situations.
All the developed sensors are able to measure the displacement along one or two axis, that can
be employed also during vibration tests especially at high frequencies, and also acceleration sensors
to monitor acceleration at low frequencies.
The developed sensors are based on plastic optical fibers instead of the traditional glass fibers,
which are traditionally employed in optical communications.
This change is related to the aim of realizing sensors maintaining the excellent typical characteristics
of the fibers, such as electromagnetic immunity, intrinsically fire safety and flexibility of
applications, but with costs comparable to those of commercial electromechanical sensors.
Indeed, nowadays, the commercial fiber optic sensors are based on glass fibers because they have
very good performance.
However, they find limited applications due to the high costs of their complex interrogation systems
and also for the procedure required to splice the fibers.
On the other hand, plastic optical fibers represent a promising alternative because of their geometrical
and optical properties that allow employing low-cost non coherent sources such as LED
and also simplifying the procedure for the sensor connection and installation.
Therefore, the design of the proposed plastic optical fiber displacement sensors is described
with the sensor practical arrangement and the realized prototypes. An acquisition system has
been designed and realized to characterize the sensors and the characterization results are also
provided. Moreover, the development and the characterization of a plastic optical fiber sensor able
to measure the displacement in two directions have been described.
The main drawback of the developed sensors are stability issues and for this reason laboratory
and in situ-tests have been carried out in order to verify the sensor performance over the time.
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The results obtained with the stability tests have highlighted the necessity to develop displacement
sensors with increased stability. To this aim, a compensation technique based on two different
wavelengths has been developed.
The same working principle of the developed displacement sensor has been exploited to realize
a fiber vibrometer to be employed during the vibration monitoring for measuring without contact
the vibrations of the device under test.
The sensor development, a suitable calibration procedure developed to overcome the problem of
real targets with a non uniform reflectivity, and the experimental tests have been described.
Furthermore, the preliminary results concerning the feasibility study of a plastic optical fiber
accelerometer are reported.
3
Okonkwo, Igweani Uchenna Titus. "Optical fiber transmission systems for in-door next generation broadband access network." Thesis, Brunel University, 2014. http://bura.brunel.ac.uk/handle/2438/10539.
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This thesis investigates the generation and radio-over-fibre (RoF) transport of unlicensed 60 GHz millimetre-wave (mm-wave) frequency band. The investigated benefits of transmission schemes applicable for the mm-wave generation include optical carrier suppression (OCS), optical frequency multiplication (OFM) and remote heterodyne detection (RHD). For the in-door cabling of the mm-wave transmission, a low-cost polymer optical fibre (POF) along with bend-insensitive single mode fibre (BI-SMF) has been investigated for short-range networks. Transporting mm-wave generated signals over POF and BI-SMF cables based on OCS scheme showed results with the highest spectral efficiency and least inter-symbol interference over a 2.5 Gbit/s data delivery. Based on this thesis analysis, OCS simulation of POF showed the most reliable power penalty performance and receiver sensitivity at 30-m whilst the BI-SMF fiber produced equal observations at 150-m and more. In observing the free space links of delivering the RoF signal, the attenuation on the received signal power for both POF and BI-SMF was insignificant but expected, as the simulation assumed complete and total collimation of the light beams onto the aperture of the photodetector. OCS scheme for mm-wave generation and transport was explored based on the cost effectiveness of using one external modulator compared to other generation schemes that utilised more than one external modulator. OFM scheme was simulated to transport LTE and Wi-Fi signals along with 60 GHz RF band through both SMF and MMF-POF/BI-SMF cables. OFM transport scheme produced the highest attenuation on LTE, Wi-Fi and mm-wave signals carrying 100 Mbit/s data as simulated POF lengths increased. The best performance POF length was observed at 10-m. The application of offset launch technique at the coupling of SMF and POF showed insignificant improvement on signal bandwidth. The free space OFM transmission also demonstrated negligible change to the received signal power. This reinforces the attributes of deploying OWC system in an in-door environment. In other investigation, the simulated successful delivery of mm-wave signal using RHD scheme modulated and transported 10 Gbit/s data signal over POF and BI-SMF cables. Additional observed unrecorded result also showed BI-SMF cable maintained a 2% reduction of received power for 450-m fiber cable from 150-m. The attributes to RHD includes its low operating power system application and delivery of localised 60 GHz signal for uplink RoF transmission. The conceptualised design of Gigabit data delivery for indoor customer applications either through POF or BI-SMF cable, transporting various wireless channels has been presented in this thesis for the design of a robust next generation Broadband access network to reinforce the fiber-inside-the-home (FiTH) deployment.
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RAMIREZ, MOLINA JULIO CESAR. "Digital Signal Processing on FPGA for Short-Range Optical Communications Systems over Plastic Optical Fiber." Doctoral thesis, Politecnico di Torino, 2012. http://hdl.handle.net/11583/2496878.
Full textAbstract:
Nowadays bandwidth requirements are increasing vertiginously. As new ways
and concepts of how to share information emerge, new ways of how to access the
web enter the market. Computers and mobile devices are only the beginning, the
spectrum of web products and services such as IPTV, VoIP, on-line gaming, etc has
been augmented by the possibility to share, store data, interact and work on the
Cloud.
The rush for bandwidth has led researchers from all over the world to enquire
themselves on how to achieve higher data rates, and it is thanks to their efforts,
that both long-haul and short-range communications systems have experienced a
huge development during the last few years. However, as the demand for higher
information throughput increases traditional short-range solutions reach their lim-
its. As a result, optical solutions are now migrating from long-haul to short-range
communication systems. As part of this trend, plastic optical fiber (POF) systems
have arisen as promising candidates for applications where traditional glass optical
fibers (GOF) are unsuitable.
POF systems feature a series of characteristics that make them very suitable for
the market requirements. More in detail, these systems are low cost, robust, easy
to handle and to install, flexible and yet tolerant to bendings. Nonetheless, these
features come at the expense of a considerable higher bandwidth limitation when
compared to GOF systems.
This thesis is aimed to the investigate the use of digital signal processing
(DSP) algorithms to overcome the bandwidth limitation in short-range optical
communications system based on POF. In particular, this dissertation presents
the design and development of DSP algorithms on field programmable gate arrays
(FPGAs) with the ultimate purpose of implementing a fully engineered 1Gbit/s
Ethernet Media Converter capable of establishing data links over 50+ meters of
PMMA-SI POF using an RC-LED as transmitter.
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Gusho, Genta. "Understanding the economics and material platform of bidirectional transceiver for plastic optical fiber." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33624.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2005.<br>Includes bibliographical references (leaves 74-76).<br>Limitations of electrical wires result in distortion and dispersion of the signal for long distances. That have emerged optical communication as the only way of communication for long distances. For medium distances optics can support the high data rates required by the latest applications. Optical networks are becoming the dominant transmission medium as the data rate required by different applications increases. The bottleneck for implementing optical instead of electric networks for medium distances, like local area network, is the cost of the optical components and the cost of replacing the existing copper network. This thesis will discuss the possible cost benefits that come from the use of different materials like plastic optical fiber instead of silica fiber or Si, Si/Ge instead of InP or GaAs for the transceiver as well as the trade offs between the performance and cost when discrete transceiver is replaced by the monolithically integrated transceiver, by using a process based cost model.<br>by Genta (Meco) Gusho.<br>M.Eng.
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Brush, Ursula Jane. "Design and Validation of an Intensity-Based POF Bend Sensor Applications in Measuring Three-Dimensional Trunk Motion." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1269456459.
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Sartiano, Demetrio. "Design of optical fiber sensors and interrogation schemes." Doctoral thesis, Universitat Politècnica de València, 2021. http://hdl.handle.net/10251/161357.
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[ES] Las fibras ópticas son dispositivos muy utilizados en el campo de las telecomunicaciones desde su descubrimiento. En las últimas décadas, las fibras ópticas comenzaron a utilizarse como sensores fotónicos. Los primeros trabajos se centraron en la medición de unas dimensiones físicas en un punto específico. Posteriormente, surgió la posibilidad de medir las propiedades de la fibra óptica en diferentes puntos a lo largo de la fibra. Este tipo de sensores se definen como sensores distribuidos. Los componentes optoelectrónicos fueron desarrollados e investigados para telecomunicaciones. Los avances en las telecomunicaciones hicieron posible el desarrollo de sistemas de interrogación para sensores de fibra óptica, creciendo en paralelo con los avances de las telecomunicaciones.
Se desarrollaron sistemas de interrogación de fibra óptica que permiten el uso de una única fibra óptica monomodo estándar como sensor que puede monitorear decenas de miles de puntos de detección al mismo tiempo. Los métodos que extraen la información de detección de la señal reflejada en la fibra óptica son los más empleados debido a la facilidad de acceso al sensor y la flexibilidad de estos sistemas. Los más estudiados son la reflectometría en dominios de tiempo y frecuencia. La reflectometría óptica en el dominio del tiempo (OTDR) fue la primera técnica utilizada para detectar la posición de los fallos en las redes de comunica-ción de fibra óptica. El OTDR sensible a la fase hizo posible detectar la elongación y la temperatura en una posición específica. Paralelamente, los gratings de Bragg (FBG) se convirtieron en los dispositivos más utilizados para implementar sensores en fibra óptica discretos. Se desarrollaron técnicas de multiplexación para realizar la detección en múltiples puntos utilizando FGBs. La reflectometría realizada interrogando arrays de FBG débiles demuestra que mejora el rendimiento del sistema en comparación al uso de una fibra monomodo.
Los sistemas de interrogatorio actuales tienen algunos inconvenientes. Algunos de ellos son velocidad de interrogatorio limitada, grandes dimensiones y alto costo. En esta tesis doctoral se desarrollaron nuevos sistemas de interrogación y sensores de fibra óptica para superar algunos de estos inconvenientes. Los sensores de fibra óptica de plástico demuestran ser una plataforma innovadora para desarrollar nuevos sensores y sistemas de interrogación de bajo costo y fáciles de implementar para fibras de plástico comerciales. Se investigó la reflectometría en el dominio del tiempo y las técnicas fotónicas de microondas para la interrogación de una matriz de rejillas débiles que permitieron simplificar el sistema de interrogación para la detección de temperatura y vibración.<br>[CA] Les fibres òptiques són dispositius molt utilitzats en el camp de les telecomunica-cions des del seu descobriment. En les últimes dècades, les fibres òptiques van començar a utilitzar-se com a sensors fotònics. Els primers treballs es van centrar en el mesurament d'unes dimensions físiques en un punt específic. Posteriorment, va sorgir la possibilitat de mesurar les propietats de la fibra òptica en diferents punts al llarg de la fibra. Aquest tipus de sensors es defineixen com a sensors distribüits. Els components optoelectrònics van ser desenvolupats i investigats per a telecomunicacions. Els avanços en les telecomunicacions van fer possi-ble el desenvolupament de sistemes d'interrogació per a sensors de fibra òptica, creixent en paral·lel amb els avanços de les telecomunicacions.
Es van desenvolupar sistemes d'interrogació de fibra òptica que permeten l'ús d'una única fibra òptica monomodo estàndard com a sensor que pot monitorar desenes de milers de punts de detecció al mateix temps. Els mètodes que extreuen la informació de detecció del senyal reflectit en la fibra òptica són els més utilitzats a causa de la facilitat d'accés al sensor i la flexibilitat d'aquests sistemes. Els més estudiats són la reflectometría en dominis de temps i freqüència. La reflectometría òptica en el domini del temps (OTDR) va ser la primera tècnica utilitzada per a detectar la posició de les fallades en les xarxes de comunicació de fibra òptica. El OTDR sensible a la fase va fer possible detectar l'elongació i la temperatura en una posició específica. Paral·lelament, els gratings de Bragg (FBG) es van convertir en els dispositius més utilitzats per a implementar sensors en fibra òptica discrets. Es van desenvolupar tècniques de multiplexació per a realitzar la detecció en múltiples punts utilitzant FGBs. La reflectometría realitzada interrogant arrays de FBG febles demostra que millora el rendiment del sistema en comparació a l'ús d'una fibra monomodo.
Els sistemes d'interrogatori actuals tenen alguns inconvenients. Alguns d'ells són velocitat d'interrogatori limitada, voluminositat i alt cost. En aquesta tesi doctoral es van desenvolupar nous sistemes d'interrogació i sensors de fibra òptica per a superar alguns d'aquests inconvenients. Els sensors de fibra òptica de plàstic demostren ser una plataforma innovadora per a desenvolupar nous sensors i siste-mes d'interrogació de baix cost i fàcils d'implementar per a fibres de plàstic comercials. Es va investigar la reflectometría en el domini del temps i les tècniques fotòniques de microones per a la interrogació d'una matriu de reixetes febles que van permetre simplificar el sistema d'interrogació per a la detecció de temperatura i vibració.<br>[EN] Optical fibers are devices largely used in telecommunication field since their discovery. In the last decades, optical fibers started to be used as photonic sensors. The first works were focused on the measurement of physical dimensions to a specific point. Afterward, emerged the possibility to measure the optical fiber properties at different locations along the fiber. These kinds of sensors are defined as distributed sensors. The optoelectronic components were developed and investigated for telecommunications. The progress in telecommunication made possible the development of optical fiber sensors interrogation systems, growing in parallel with the advances of telecommunications.
Optical fiber interrogation systems were developed to use a single standard monomode optical fiber as a sensor that can monitor tens of thousands of sensing points at the same time. The methods that extract the sensing information from the backscattered signal in the optical fiber are widely employed because of the easiness of access to the sensor element and the flexibility of these systems. The most studied are the reflectometry in time and frequency domains. The optical time domain reflectometry (OTDR) was the first technique used to detect the position of the failures in the optical fiber communication networks. Using phase sensitive OTDR it is possible to sense strain and temperature at a specific position. In parallel, fiber Bragg gratings (FBGs) became the most widely used devices to implement discrete optical fiber sensors. Multiplexing techniques were developed to perform multi points sensing using these gratings. The reflectometry performed interrogating weak FBGs arrays demonstrate to improve the performance of the system employing a single mode fiber.
The interrogation systems nowadays have some drawbacks. Some of them are limited speed of interrogation, bulkiness, and high cost. New interrogation systems and optical fiber sensors were developed in this doctoral thesis to overcome some of these drawbacks. Plastic optical fiber sensors demonstrate to be an innovative platform to develop both new sensors and low cost, easy to implement interrogation systems for commercial plastic fibers. Reflectometry in time domain and microwave photonic techniques were investigated for the interrogation of weak gratings array allowed to simplify the interrogation system for the sensing of temperature and vibration.<br>I would like to greatly thank the European Union’s Horizon 2020 Research and Innovation Program that funded the research described in this thesis under the Marie Sklodowska-Curie Action Grant Agreement 722509.<br>Sartiano, D. (2021). Design of optical fiber sensors and interrogation schemes [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/161357<br>TESIS
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Nurgiyatna, Nurgiyatna. "Tomography imaging based on plastic optical fibre." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/tomography-imaging-based-on-plastic-optical-fibre(481b898a-b1dc-49ae-aa3f-3555a982bb75).html.
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Plastic optical fibres (POF) can be made sensitive to various parameters. Therefore, a successful implementation of tomographic imaging based on POF sensors will open the way to develop imagers for various parameters utilising this inexpensive sensor material. The work reported in this thesis is aiming to implement real time tomographic imaging based on the POF sensor. As the system uses light (photons) guided along the sensor to capture the information and deliver a signal at the periphery of the sensor, this technique is referred to as Photonic Guided Path Tomography (PGPT). As an initial stage of the work, we perform systematic testing of the sensitivity of POF transmission to bending. The results confirm that grooving can enhance this sensitivity of the POF sensor. They also provide an empirical proof of the anticipated changes in transmission loss by positive and negative bending for grooved POF (opening and closing of grooves respectively). We show that small positive bending increases the power loss, while for negative bending the power loss experiences a minimum, corresponding to the best achievable waveguiding recovery because of the closing of grooves. Beyond certain deformation, the sensitivity of the POF sensor is dominated by losses in the un-grooved regions. A bending test for the mechanical integrity of grooved POFs shows that repetitive bending to a small radius results in a quick deterioration depending on the depth of the groove. However for bending radii more than 20mm and groove depths up to 0.3mm, the lifetime of the POF sensor is still acceptable for many targeted sensor application.While it is clear that the grooved POF is more sensitive to small bending compared to the un-grooved POF, the latter offers uncompromised mechanical integrity and is more desirable when the highest possible sensitivity is not a priority. Therefore, in the final stage of the work, both grooved and un-grooved POF are considered as candidates for developing the tomographic imaging modality. Further detail is considered in view of the targeted deliverable, a real PGPT system for footstep imaging, based on POF sensors. This has been successfully achieved by designing, integrating and testing two different PGPT systems: one based on grooved POF with sensor head size of 0.9m x 0.9m incorporating a multiplexed photodetector and another based on un-grooved POF with sensor head size of 2m x 1m, incorporating independent POF sensors. Both are capable of performing the real time imaging task as well as storing the numerical data for alternative processing. The image reconstruction is by applying a median-filtered Landweber method to solve the inverse tomography problem. The frame rate achieved is 2Hz and 1Hz with spatial resolution estimated as 10cm and 3cm for the first and second system respectively
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Ioannides, Nicos. "Novel opto-electronic and plastic optical fibre sensors." Thesis, London Metropolitan University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287610.
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The design and performance of a novel displacement sensor is investigated both theoretically and experimentally. This is an optical, extrinsic and differential sensor based on the inverse square law and is insensitive to source intensity variations. It can, in principle, be implemented using only opto-electronic components or it can incorporate optical fibres to allow for EMI free and remote operation. The sensor is implemented using Plastic Optical Fibres (POF) as these offer considerable advantages over glass fibres or glass fibre bundles. The sensor head consists of three POFs positioned side by side and displaced from each other parallel to the axis of the sensor head by a separation X, (mm). The middle POF is coupled to a red LED and emits light onto a flat target with the two outer fibres receiving the reflected light from the target and guiding it to two silicon PIN photodiodes. Theoretical investigations on the behaviour of the sensor are presented for ranges between 0 mm and 100 mm, and for targets with different reflectivities. Non-linearities in the form of a spike are shown to exist in the very short ranges resulting in a minimum operational range of about 15 nun Beyond this minimum range the sensor response is linear and depends on the reflectivity of the target, the accuracy of calibration between the two detectors, any offset voltage present in any of the detectors, possible errors on the detected signals and the X, separation which in principle can be used to scale the sensor. Experimental results obtained confirm the long and linear operational range of the sensor (between 15 mm and 90 mm for a mirror target and between 20 mm and 100 mm for a matt white paper target). Likely variations in the source light intensity do not affect the performance and accuracy of the sensor. Measurements performed with various X, separations verify the scalability feature of the sensor in that by increasing X, one can achieve longer operational ranges. Temperature variations up to 40 °c do not affect the linearity of response. Effects arising from angular misalignment of the target and! or the ends of the three POFs are also investigated and could be minimised by rotating the emitting POF. Matt white paper is concluded as the preferred type of target since it offers a longer linear operational range with less stringent alignment requirements as opposed to reflective targets. Operation of the sensor under ambient illumination conditions is demonstrated using suitable electronic circuitry with filtering facilities. The result is a linear operational range of 60 mm with 1 % accuracy with a matt white paper target. An automated version of the sensor under software control is also demonstrated for monitoring large amplitude (0.15 mm - 6 mm), single degree vibrations. The maximum determined frequency of the vibrating surface is about 150 Hz and this is only limited by the target displacement which is close to the resolution limits of this version of the sensor (0.15 mm). This novel sensor offers considerable advantages over other sensors reported in the literature. It is shown to offer a very long and linear operational range in excess of 100 mm, with accuracy better than 1% and resolution better than 0.2 % of range, and currently this performance is only limited by the electronic circuitry used. Overall, the proposed sensor offers a superior sensor head arrangement and performance combination and its cost is expected to be very low. Suggestions for improvements and other applications are offered.
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Wong, Yuen Mei. "Optimising the plastic optical fibre evanescent field biofilm sensor." Thesis, Liverpool John Moores University, 2008. http://researchonline.ljmu.ac.uk/5906/.
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This thesis describes the development, characterisation and application of large diameter multimode plastic optical fibre (POF) sensors using evanescent field modulation. The exposed polymethylmethacrylate (PMMA) core of the POF fibre forms the sensor interface that detects refractive index changes of a measurand acting as the cladding. When a liquid measurand is used, the sensor can detect changes in refractive index, absorption and suspended particulates. It is this simple mechanism by which the evanescent field POF sensor operates. The evanescent field POF sensor has been characterised for refractive index of surrounding liquid from 1.33 to 1.49. The sensor demonstrated accuracy of ± 7x 10-3 refractive index units below 1.4 and ±2x 10-3 refractive index units above 1.4. Components have been selected and designed for this project to ruggedise the sensor, to make the sensor more self-contained and cheaper. The original design of the test conditions did not allow for optimum deployment of the sensor as it stripped out the very modes of light that were required for sensing purposes. The system was also operating under pressure, not reflecting the real conditions under which the sensor would be operating. The re-design of test conditions holds the sensor without straining the POF and operates under normal atmospheric pressure. The POF sensor was demonstrated reacting to a real measurand eg biofilm in which initial growth affects the optical properties at the core cladding interface by refractive index modulation. This sensor was capable of measuring biofouling and scaling at water interfaces. The sensor was trialled in a European Commission funded project (CLOOPT) to study biofouling and scaling in closed loop water systems such as heat exchangers in the cooling tower of an electric power plant, and as an interface sensor for water quality monitoring (AQUA-STEW) involving biofilm removal and surface cleansing with a new application for contact lens protein removal systems. Tapering multimode POF was a desirable goal as this increases the proportion of light coupled into the core available for sensing purposes, to achieve a more sensitive evanescent field POF sensor. Optically clear and consistent smooth tapering of ends and mid-lengths of POF fibre were achieved through chemical removal of material. The tapered POF sensor was characterised with a range of refractive indices, and it exhibited two distinct regions; the water/alcohol region below 1.4 refractive index units, and the oil region above 1.4 suggesting the sensor's use as an oil-in-water, or water-in-oil sensor. From 95% confidence limits, the accuracy of the POF was ±O.006 refractive index units (to 2 standard deviations) for fluids of refractive indices above 1.4. Tapered POF is sensitive to refractive index providing a cheap, easy to handle and rugged throwaway sensor for water and beverage process and quality monitoring.
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Quiroga, Oranday Gustavo. "Thermal-mechanical characterization and analysis of bending of plastic optical fibers." Ann Arbor, Mich. : ProQuest, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1434829.
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Thesis (M.S. in Mechanical Engineering)--S.M.U.<br>Title from PDF title page (viewed July 13, 2007). Source: Masters Abstracts International, Volume: 44-06, page: 2978. Adviser: Wei Tong. Includes bibliographical references.
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Bridle, Christopher Michael. "The use of thermotropic liquid crystal polymers in optical fibre cable applications." Thesis, Brunel University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293024.
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Stevens, Renaud. "Modulation Properties of Vertical Cavity Light Emitters." Doctoral thesis, Stockholm : Tekniska högsk, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3240.
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Thibodeau, Elisabeth Gabrielle. "Static and Fatigue Fracture Characterization of Primary and Secondary Bonded Woven E-Glass Composites." Fogler Library, University of Maine, 2007. http://www.library.umaine.edu/theses/pdf/ThibodeauEG2007.pdf.
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Fifield, Samantha D. "Experimental Methodology for Embedding Fiber Optic Strain Sensors in Fiber Reinforced Composites Fabricated by the VARTM/SCRIMP Process." Fogler Library, University of Maine, 2002. http://www.library.umaine.edu/theses/pdf/FifieldSD2002.pdf.
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Morales, Johnny Estuardo. "The development of a plastic scintillator for radiotherapy dosimetry." Department of Engineering Physics - Faculty of Engineering, 2008. http://ro.uow.edu.au/theses/105.
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A plastic scintillator detector was developed and tested in a 6MV photon beam. The detector comprised a BCF60 plastic scintillator, Polymetyl-Methacrylate Resin optical fibre and photodiode SFH250. The detector was used to measure an inplane profile for the photon beam at a depth of 1.5 cm for a field size of 10x10cm2 at 100 cm SSD. The photon beam was delivered by a Siemens linear accelerator. A comparison was made with the results obtained by cylindrical chambers CC04 and CC13, commercial diode PFD and a stereotactic diode SFD, all from the manufacturer IBA-Wellhöfer. An analysis was performed using the Gamma Evaluation method and the agreement was acceptable for a criterion of Distance To Agreement = 2 mm and Dose Difference = 2%.
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El-Chiti, Fadi. "Experimental Variability of E-Glass Reinforced Vinyl Ester Composites Fabricated by VARTM/Scrimp." Fogler Library, University of Maine, 2005. http://www.library.umaine.edu/theses/pdf/El-ChitiF2005.pdf.
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Camak, Burak. "Modeling On Rayleigh Scattering In Optical Waveguides." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1251675/index.pdf.
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In the last few years, interest in polymer optical fibers (POF) has increased because of
their low cost, easy handling and good flexibility even at large diameters. Moreover,
optical cables do not have the problem of electromagnetic interference, which gives, for
instance, the problem of cross-talk in copper telephone cables. In the usage of current
communication and computer systems the yield has gained a big importance and it has
seen from studies that light scattering loss is the only loss, which cannot be eliminated
entirely. Besides, this loss causes its attenuation loss intrinsically and determines the
lower limit of loss in the POF.
In this work, the importance and the dependencies of light scattering were studied, and
calculations were done in order to find more appropriate polymer for using as core
material of POFs. For this aim, a computer program that calculates the light scattering
loss of several amorphous polymers and plots the graph of isotropic scattering loss versus isothermal compressibility and total attenuation loss versus wavelength was
written.
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Voigt, Yixuan [Verfasser], and Joachim [Akademischer Betreuer] Speidel. "Digital pre- and post-equalizers for in-car data transmission over plastic optical fibers / Yixuan Voigt. Betreuer: Joachim Speidel." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2015. http://d-nb.info/1065235968/34.
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Correia, Sandra Filipa Henriques. "Organic-inorganic hybrid materials for green photonics: luminescent solar concentrators." Doctoral thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/17407.
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Doutoramento em Física<br>Luminescent solar concentrators are inexpensive devices that aim to increase the efficiency of photovoltaic cells and promote the urban integration of photovoltaic devices, with unprecedented possibilities of energy harvesting through the façade of buildings, urban furniture or wearable fabrics. Generally, they consist of a transparent matrix coated or doped with active optical centres that absorb the incident solar radiation, which is re-emitted at a specific wavelength and transferred by total internal reflection to the edges where the photovoltaic cells are located. The main objective of this work is the production of luminescent solar concentrators whose optically active layer is based on organic-inorganic hybrid materials doped with europium ions or organic dyes, in particular, Rhodamine 6G and Rhodamine 800. Rhodamine 800, as opposed to europium ions and Rhodamine 6G which emit in the visible range, emits in the near infrared (NIR) range, which is an advantage for crystalline Si-based photovoltaic cells, whose efficiency is greater in the NIR. In this work, although the luminescent solar concentrators with planar geometry are addressed, the main focus is the use cylindrical geometry. The use of this type of geometry allows the effect of concentration to be higher relative to the planar geometry, since the ratio between the exposed area and the area of the edges is increased. The cylindrical geometry is exploited by producing luminescent solar concentrators based on polymer optical fibre (plastic) where the optically active layer is on the outside (as a coating) or inside (as a filling in the hollow core) of the optical fibre. Furthermore, the possibility of increasing the exposed area was also dealt with the production of bundles of luminescent solar concentrators in which the plastic optical fibres are placed side by side and, also, by fabricating luminescent solar concentrators with length in the metre scale.<br>Os concentradores solares luminescentes são dispositivos de baixo custo que têm como objetivo aumentar a eficiência de células fotovoltaicas e promover a integração de dispositivos fotovoltaicos em elementos do dia-a-dia, tornando possível a captura de energia solar, através da fachada de edifícios, mobiliário urbano ou em têxteis. Geralmente, consistem numa matriz transparente coberta ou dopada com centros óticos ativos, capazes de absorver a radiação solar incidente e reemiti-la com um comprimento de onda específico que será transportada, através de reflexão interna total, para as extremidades da matriz onde se encontra(m) a(s) célula(s) fotovoltaica(s). O principal objetivo deste trabalho consiste na produção de concentradores solares luminescentes cuja camada ótica ativa é baseada em materiais híbridos orgânicos-inorgânicos dopados com iões lantanídeos (európio, Eu3+) ou corantes orgânicos, nomeadamente, Rodamina 6G e Rodamina 800. A Rodamina 800, ao contrário dos iões de európio e da Rodamina 6G que emitem na gama do visível, emite na região espetral do infravermelho próximo (NIR), que se revela uma vantagem quando a célula fotovoltaica em uso é composta de silício cristalino, cuja gama de maior eficiência é no NIR. Neste trabalho, apesar de serem abordados concentradores solares luminescentes com geometria planar, o principal foco é a utilização da geometria cilíndrica. Este tipo de geometria permite que o efeito de concentração seja superior, relativamente à geometria planar, uma vez que a razão entre a área exposta e a área das extremidades é aumentada. A geometria cilíndrica é explorada, através da produção de concentradores solares luminescentes com base em fibra ótica polimérica (plástica) em que a camada ótica ativa se encontra no exterior (como um revestimento) ou no interior (como um preenchimento do núcleo oco). Além disso, a possibilidade de aumentar a área exposta foi, também, abordada com o fabrico de uma matriz de concentradores solares luminescentes colocados lado a lado e, também, com o fabrico de concentradores solares luminescentes na escala do metro.
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Ulbricht, Andreas, Maik Gude, Daniel Barfuß, Michael Birke, Andree Schwaar, and Andrzej Czulak. "Potential and application fields of lightweight hydraulic components in multi-material design." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-200294.
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Hydraulic systems are used in many fields of applications for different functions like energy storage in hybrid systems. Generally the mass of hydraulic systems plays a key role especially for mobile hydraulics (construction machines, trucks, cars) and hydraulic aircraft systems. The main product properties like energy efficiency or payload can be improved by reducing the mass. In this connection carbon fiber reinforced plastics (CFRP) with their superior specific strength and stiffness open up new chances to acquire new lightweight potentials compared to metallic components. However, complex quality control and failure identification slow down the substitution of metals by fiber-reinforced plastics (FRP). But the lower manufacturing temperatures of FRP compared to metals allow the integration of sensors within FRP-components. These sensors then can be advantageously used for many functions like quality control during the manufacturing process or structural health monitoring (SHM) for failure detection during their life cycle. Thus, lightweight hydraulic components made of composite materials as well as sensor integration in composite components are a main fields of research and development at the Institute of Lightweight Engineering and Polymer Technology (ILK) of the TU Dresden as well as at the Leichtbau-Zentrum Sachsen GmbH (LZS).
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Heidarialamdarloo, Jamshid. "Advanced communications with plastic optical fibers." Doctoral thesis, 2018. http://hdl.handle.net/10773/25881.
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Nowadays, fiber to the Home/Curb/Building/Cabinet (FTTx) services that interconnect homes with a standard glass optical fiber cables to the core/access optical networks have brought the optical fiber at the doorsteps of our homes. However, the last few miles in home access network is still based on the limited bandwidth electronic component which supports by the cooper wires e.g. Cat-5, 6. The rapid growth of personal smart/mobile electronic devices with new developments such as video on demand, High Definition (HD)
and three-Dimension (3D) television (TV), cloud computing, video conferences, etc. has been proposed new challenges for the next generation high bandwidth demand required for subscribers in home access network. In order to meet the more demanding expectations of the end user with new developments, it is necessary to improve the physical infrastructure of the existing in home networks in order to obtain the best ratio between quality of service and price of implementation. Plastic optical fibers (POFs) are point out as a promising transmission medium for short-range communication in compare to the “classic” single/multimode glass optical fibers and current cooper wire
technology developments. The main advantages of POF are its easy to install, easy splicing and the possibility of using low cost optical transceivers, capability of being robust, and immunity to electromagnetic noise interference. However, the benefits of large-core POFs come at the expense of a less bandwidth and a higher attenuation than silica-based solution. The main objective of this doctoral dissertation is to explore the possibilities and develop low cost, short reach, high data rate POF-links for in home
networks applications. This thesis investigates the use of multilevel modulation in particular, pulse amplitude modulation (PAM in combination of the receiver equalizer in order to overcome the bandwidth limitations of the graded index POFs. The possibility of the using multiple channels over a single fiber to increase the capacity of POF systems using commercially available multimode components is also analyzed in this dissertation. Moreover, a low cost Digitised radio signal over plastic fiber system is proposed and evaluated to deliver digital baseband data for wireline and wireless users in home access network. The deployment will be specified in terms of performance, maximum rates and any degradation that might appear in the network. Furthermore, the possibilities of the microstructured fibers in telecommunication application will be studied with main emphasis on their structural design. The photonic crystal fibers made of different highly nonlinear materials with different structures are optimized to achieve ultra-flat dispersion, high nonlinearity and low confinement loss over a broad range of wavelengths in the perspective of their usage in telecommunication applications.<br>Hoje em dia, a possibilidade de a fibra óptica até casa (FTTH) para a transmissão simultânea de diferentes serviços como internet, telefone, televisão digital é uma realidade. No entanto, para satisfazer as expectativas mais exigentes do usuário final com novos desenvolvimentos, tais como vídeo sob demanda, de alta definição (HD) e tridimensional (3D) de televisão (TV), computação em nuvem, vídeo conferências, etc., é necessário melhorar a infra-estrutura física da existente em redes domésticas, a fim de obter a melhor relação entre a qualidade do serviço e preço de implementação. Fibra óptica de plástico (POF) é considerada um meio de transmissão promissor para
comunicações de curto alcance, queando comparadas com a clássica fibra óptica de silica (tanto monomodo como multimodo) e com as tecnologias atuais baseadas em fio de cobre. As principais vantagens da POF encontramse na sua facilidade de instalação e conecção, possibilidade de uso de fontes e detectores de baixo custo, robustez e imunidade electromagnética. No entanto, o uso da POF de elevado diâmetro têm também desvantagens uma vez que esta oferece uma menor largura de banda e uma atenuação superior à
fibra de sílica convêncional. Esta dissertação de doutoramento tem como principal objetivo explorar as possibilidades de desemvolvimento de componentes de baixo custo baseados em POF para redes de curto alcance, com alta taxa de transmisssão de dados. Esta tese investiga a utilização de vários formatos de modulação combinados
com equalizador e receptor, de maneira a superar as limitações de largura de banda em sistemas de comunicação óptica de curto alcance. Em particular, a modulação em amplitude de impulso (PAM) é proposta e investigada a fim de aumentar a capacidade de tais sistemas. Além disso, a possibilidade de usar múltiplos canais, utilizando uma única fibra óptica, também conhecido por multiplexagem por divisão de comprimento de onda (WDM), será analisada neste trabalho. A viabilidade das tecnologias de redes de acesso tanto a nível individual como em sistemas WDM serão analisadas usando componentes multimodo disponíveis comercialmente. A implementação será especificada
em termos de desempenho tanto a nível da taxas máximas de transmissão, bem como na degradação do sinal que possa ocorrer na rede. No capitulo 5 desta dissertação é apresentado sistema de radio através de fibra. Este tipo de sistemas permite a simplificação das estações base providenciando também uma elevada manutenção de custos. O principal objectivo deste estudo prende-se com a investigação do impacto da amostragem na preformance de digitalização de rádio através de fibra e também como a introdução de fibra óptica de plástico pode afetar o sistema. Além disso, a possibilidade da aplicação de fibras óticas microestruturadas em redes de telecomunicações serão estudadas com ênfase principal na sua concepção estrutural. As fibras de cristal fotônico feitas de diferentes materiais altamente não-lineares com diferentes estruturas serão otimizadas a fim de alcançar uma dispersão ultra-plana, elevada não linearidade e baixa perda de confinamento em uma vasta gama espectral, na perspectiva de seu uso em aplicações de telecomunicações.<br>Programa Doutoral em Engenharia Eletrotécnica
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Tei-Wei, Chan, and 詹德威. "Video Communication System Using Plastic Optical Fiber." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/15927781562730338398.
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He, Jheng-hong, and 何政泓. "A Plastic Optical Fiber-based Polarization Scrambler." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/52934137552428969104.
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碩士<br>國立臺灣科技大學<br>電子工程系<br>103<br>Polarization scramblers have become an important component in high speed optical communication systems. Mitigating the polarization related impairments, we propose a plastic optical fiber-based polarization scrambler to reducing the degree of polarization. In this paper, a 50 m length plastic optical fiber and two optical sources Fabry-Perot Laser Diode of 1310 nm wavelength and LED of 1310 nm wavelength are employed to measure the decrease in degree of polarization. We launched FPLD and LED light source passing through the POF, SMF and MMF and got the results of degree of polarization from polarization analyzer. In the proposed approach, we demonstrate the maximum differences of degree of polarization are 39.2% and 1.4% for FPLD and LED.
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Su, Heng-Sheng, and 蘇恒生. "Studies and Applications of Using Novel Plastic Optical Fiber to Setup Fiber Optical CATV / Radio-over-Fiber Transport Systems." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/56775685607657360858.
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博士<br>國立臺北科技大學<br>光電工程系研究所<br>100<br>Optical fiber with characteristics like low attenuation, high bandwidth, high speed, and electromagnetic noise interference (EMI) free is widely used in constructing communication transport systems. As a communication medium, glass single-mode fiber (SMF) offers much better performances than plastic optical fiber (POF). Also, glass single-mode fiber (SMF) can apply in backbone and access network. Nevertheless, fiber optical communication systems for last mile end user applications have not yet addressed. Building a feasible and an economical technique structure to fit in with last mile end user applications is a big challenge.
In recent years, some new POFs, such as perfluorinated graded-index plastic optical fiber (PF GI-POF), have been developed with better performance and low cost. In this dissertation, we present several ways to verify optical transport systems access network with build-in PF GI-POF. PF GI-POF access network can be a candidate for last mile end user applications.
Furthermore, we proposed two light sources and demonstrated that they can conform to application of fiber-to-the-X (FTTX) and radio over fiber (ROF) transport system, respectively. One light source based on a broadband amplified spontaneous emission (ASE) is for FTTX/ROF transport system; the other light source combined an economical multi-band optical carrier generator with a novel optical signal to noise ratio (OSNR) enhancement circuit is for radio over fiber transport systems.
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Su, Heng-Sheng, and 蘇?琤. "Studies and Applications of Using Novel Plastic Optical Fiber to Setup Fiber Optical CATV / Radio-over-Fiber Transport Systems." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/hkr23c.
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博士<br>國立臺北科技大學<br>光電工程系研究所<br>100<br>Optical fiber with characteristics like low attenuation, high bandwidth, high speed, and electromagnetic noise interference (EMI) free is widely used in constructing communication transport systems. As a communication medium, glass single-mode fiber (SMF) offers much better performances than plastic optical fiber (POF). Also, glass single-mode fiber (SMF) can apply in backbone and access network. Nevertheless, fiber optical communication systems for last mile end user applications have not yet addressed. Building a feasible and an economical technique structure to fit in with last mile end user applications is a big challenge.
In recent years, some new POFs, such as perfluorinated graded-index plastic optical fiber (PF GI-POF), have been developed with better performance and low cost. In this dissertation, we present several ways to verify optical transport systems access network with build-in PF GI-POF. PF GI-POF access network can be a candidate for last mile end user applications.
Furthermore, we proposed two light sources and demonstrated that they can conform to application of fiber-to-the-X (FTTX) and radio over fiber (ROF) transport system, respectively. One light source based on a broadband amplified spontaneous emission (ASE) is for FTTX/ROF transport system; the other light source combined an economical multi-band optical carrier generator with a novel optical signal to noise ratio (OSNR) enhancement circuit is for radio over fiber transport systems.
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chen, Ru-yan, and 陳彥儒. "Manufacturing Technique of 1D Lens Plastic Optical Fiber Array." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/tgz2kz.
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碩士<br>國立中山大學<br>機械與機電工程學系研究所<br>95<br>The research is focus on manufacturing one dimension lens plastic optical fiber array, carrying out by electrostatic force was applied to shape polymer liquid from hemisphere into paraboloid or near cone shape. In manufacturing process, the lens will be slanted by electrostatic force, so we shorten the electrode to solve the problem, and shorten the distance between fiber and fiber to manufacture the most small volume of the fiber array. To combine the two methods, we can manufacture the high coupling efficiency of the one dimension lens plastic optical fiber array.
Finally, the above improved strategies are verified by the simulation and experimental results.
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Liao, Shir-Jie, and 廖士杰. "Investigation of Bending Surface Plasmon Resonance Based Plastic Optical Fiber." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/m48ucg.
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碩士<br>銘傳大學<br>電子工程學系碩士班<br>105<br>In this paper, we make a surface plasmon resonance based plastic optical fiber sensor and study the bending effect and the structure of the cascade sensing area to improve sensor’s performance. In order to increase the sensitivity of sensor, three parameters were changed including optical fiber diameter, bending and sensing area. In experiment, we use glycerol solution to measure the SPR transmittance for cascade sensor and find the variation of transmittance could be superimposed, which performed double amount. In the bending experiment, we found the optimum bending diameter was 6 cm, which had best sensitivity and increased 374 nm/RIU. The optimized sensor structure, which is cascade and bending, was applied for glucose solution measurement. It results in sensitivity increasing 172 nm/RIU and variation of transmittance is 1.43 times than that of the original. Finally, for energy intensity measurement, our proposed SPR sensor was applied to respiration monitoring. The experimental results show better performance than that with bare plastic optical fiber by 0.69 dBm. Not only measuring the breathing frequency, it can also provide clearly breathing depth change.
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Chou, Chien-yu, and 周建宇. "Light Coupling of LED Plastic Optical Fiber: Design and Application." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/57949026617113675805.
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碩士<br>國立臺灣科技大學<br>電子工程系<br>98<br>The thesis presents the guide-light structure by using fiber to deliver the visible light. We put LEDs where they can be easily replaced, repaired such as locate at neat floor. Then optical components are used to couple visible light and plastic optical fiber (POF) is used as transmission medium. The guide-light structure also composed of LED TIR lens and Fresnel lens to increase the coupling efficiency. The light-coupling research focus on LED TIR lens and Fresnel lens design, respectively. In order to allow more convenient add or drop LED numbers, both TIR lens and Fresnel lens are used. Firstly, the divergent light source can be transferred into a parallel light by using TIR lens, then the parallel light goes through the Fresnel lens and finally arrives the POF with high coupling efficiency. All the processes are designed by FRED. The key point for TIR lens design are on parabolic reflector and the convex surface. According to various parabolic focal lengths, we analyze the effect of the light emitting efficiency and the angular displacement. The LED constitutes ±10 degree angle of the light distribution for a Lambertian distribution LED. The design of Fresnel lens is based on designing approach let the ring to face imaging space. The coupling efficiency is analyzed according to vary the ring numbers and focal length. The parallel light source goes through the Fresnel lens and then transfer into a spotlight before couple into POF, where high coupling efficiency up to 84.4% may be obtained. Based on the same method to integrate TIR lens and Fresnel lens together in simulation, we can calculate the average coupling efficiency per LED lamp no matter how many LEDs are used., The average coupling efficiency are increase from 71.28% for 2 LEDs to 57.79% for 7 LEDs. Total power is 142.60 lm for 2 LEDs and404.53 lm for 7 LEDs with 3 to 6 LED lamps in between. In summary, the visible light can be coupled into POF by appropriately design optical structure so as to reduce the required LED lamps.
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Dong, Yunzhi. "A High-speed Fiber-optic Receiver for Plastic Optical Fiber Applications in 65 nm CMOS process." Thesis, 2012. http://hdl.handle.net/1807/33978.
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This dissertation explores a few techniques to realize a low-cost monolithic fiber-optic receiver with large-area photo detectors in advanced CMOS processes that could potentially support multi-gigabit digital data across 10 to 20 meters plastic optical fibers (POF). The first techniques investigated in this dissertation are the use of an external pseudo-differential photo detector chip to reduce the impact of the inductive parasitics, and the use of a cross-coupled regulated-cascode (CC-RGC) buffer to relieve the DC voltage headroom issues found in conventional regulated-cascode (RGC) buffers in technologies with low power supply voltages. The second technique investigated in this thesis is the super-Gm transimpedance amplifier (SGM-TIA) that can be used to produce a very small input impedance in order to drive a very large parasitic capacitance exhibited by an integrated photo detector in advanced CMOS processes. The third technique investigated is a linear equalizer with multiple shunt-shunt feedbacks that can be utilized to produce a slowly-rising peaking response in order to compensate for the frequency-dependent losses exhibited by the integrated NW/P-sub photo detector. Two prototype POF receiver test chips have been implemented in TSMC’s 65 nm CMOS processes and non-return-to-zero optical data transmissions have been demonstrated at data rates up to 3.125 Gbps and 4.25 Gbps, respectively, with a 2.5 Gbps grade 670 nm vertical-cavity surface-emitting laser based electro-optical transmitter.
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蕭錦堂. "A Design of Resonant Cavity LED for the Plastic Optical Fiber." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/93808991549267878034.
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碩士<br>國立彰化師範大學<br>電機工程學系<br>96<br>Different light sources used for fiber application were studied in this thesis. Different light source applications are explained by the introduction of fiber type, structure and basic theory. By means of total reflection, the light source can be transmitted in the fiber core. By the material, there are two types: glass fiber and plastic optical fiber (POF). They are applied to the transmission of long distance and short distance respectively. The fiber light source is determined by wavelength. Each wavelength has different loss in different fiber material, while the wavelength of 1310nm or 1550nm are used in glass fiber, 650nm wavelength is used in POF and 850nm is for shore distances transmission. The process and performance analysis of 650nm resonant cavity LED (RCLED) was discussed in this paper.
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Hsu, Chih-Yuan, and 許致遠. "A Research of Competitiveness on Plastic Optical Fiber Transmitting Module Industry." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/00064611439076935063.
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碩士<br>國立交通大學<br>國際經貿學程碩士班<br>91<br>Global POF communications market value in 1995 was approximately $100 million, $350 million in 2000, and expected to reach $700 million in 2006 — 7 times growth in 10 years. This research is dedicated to analyze the POF Transmitter market, which holds approximately one quarter of the total market value, and discuss the competitiveness and future of all the firms in the supply chain of this industry.
This research is focused on the interviews with 15 firms in the POF industry, supported with secondary data. The observation have discovered that many upper stream and down stream firms are building new strategic alliances, while old alliances are breaking up, therefore, it is apparent that the industry is re-organizing. Almost all of the top 3 firms before 2002 are being replaced in 2003.
The findings in this research shows that most of the LED Packaging firms do not posses much competitiveness in price or technical support, it is difficult for them to maintain their relationship with their suppliers and customers, while competing with both sides. Competition will only result in price deductions. Vertical integration lead by IC design firms with technical background or connector companies possessing end customers is the best way to exhibit strong competitiveness in the highly competing market.
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Huang, Chuang-Wei, and 黃椿煒. "The Study of Long Wavelength Plastic Optical Fiber Integrated in Multiplexer/Demultiplexer." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/45143139611194586574.
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碩士<br>長庚大學<br>光電工程研究所<br>92<br>Polymers material have regarded as promising candidates for applying to short-optical communication and integrated optics. The CYTOP (Amorphous Fluorocarbon Polymer) than PMMA (Polymethyl methacrylate) extremely good low optical attenuation, low material dispersion, high transmittance and low water absorptive for optical communication system.
In this thesis, we propose that the short network uses plastic optical fiber made of amorphous fluorocarbon polymer; the plastic optical fiber transparent for a wide range wavelength from 600nm to 1300nm. And designs for phased-array wavelength division multiplexers based on self-imaging properties of multimode interference (MMI) couplers are presented.
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Chang, Hua-Chun, and 張華均. "Effect of Plastic Strain Energy Density on Polymer Optical Fiber Power Losses." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/94895911264870414762.
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碩士<br>國立屏東科技大學<br>車輛工程系碩士班<br>94<br>This thesis explores the dependence of power losses on average plastic energy densities (APED) as rays propagate along deformed polymer optical fibers (POFs). The effects of various bend radii, elongation speeds, and temperatures on the power losses in the deformed POFs are explored. The power losses in the deformed POFs are analyzed both experimentally and numerically. Three-dimensional elastic-plastic finite element models are used to simulate the plastic deformation of deformed POFs. Contact elements are used to model the interaction between the POF and disc. The results indicate that bending elongation significantly affects the power loss of a POF. The power loss becomes obvious as the elongation increases. The power loss decreases either as the elongation speed decreases or as the temperature increases.
The results also indicate that the APED introduced in a deformed POF can be considered as a key index to study the power loss. The APED can be calculated from the measured data in a tensile test. Based on the experimental results, a curve-fitted equation is proposed to estimate the power loss using the average plastic energy density for various bend radii, elongation speeds and temperatures. A good agreement between the measured results and the results simulated from the proposed model is obtained. The maximum difference is less than 6 %.
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Fu, Chang Chang, and 張昌富. "Optimization of Processing Methods and Transmission Loss of the Step-Index Plastic Optical Fiber." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/38281692627703362685.
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碩士<br>國立臺灣科技大學<br>高分子工程系<br>93<br>This study investigated the optimization of processing that the Fluoro copolymer for the cladding material of plastic optical fiber cover the core material which include Poly methyl methacrylate (PMMA), Poly Carbonate（PC）, Poly Styrene（PS）and ARTON, ZEONEX, TOPAS of Metallocene Cyclic Olefin Copolymer (MCOC ) series plastic product in plastic optical fiber sample transmission loss and research its mechanism . The result shows that select proper core material TOPAS of MCOC series plastic product to match the cladding material which made up of the plastic optical fiber sample and the optimization of processing methods to process the SI type plastic optical fiber. It is transmitted under the wavelength 660nm and 850nm of light source can make people very surprised which the low transmission of plastic optical fiber. It can obvious that transmission loss lower PMMA, PC, PS of core material which made up the plastic optical fiber .In order to understand these above-mentioned low transmission loss behavior of the plastic optical fiber. The plastic optical fiber that resisting tensile mechanics, polymer basic rheological behavior, dynamic mechanical properties of polymer, thermal properties and morphology of cross-section was further discussed in this study.
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Sousa, Artur Neves e. "Transmission techniques for high rates in optical fiber and alternative media." Doctoral thesis, 2020. http://hdl.handle.net/10773/31994.
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The increase in services provided by mobile network operators, as well as
traffic over wireless networks (WiFi), has intensely exploited the available radio
frequency (RF) spectrum. The fixed telecommunications network that connects
radio antennas, Wi-Fi access points, or other technologies (eg, Wimax)
supports new services that require higher transmission rates and connections,
such as cloud computing, HDTV, Internet of Things (IoT) or Machine-to-
Machine (M2M) communication. Silicon single-mode fiber optic (SMF) has
been chosen as a means of transporting data on the fixed network as it offers
higher bandwidths and transmission rates.
In a desirable ubiquitous and transparent optical network context, there are still
several bottlenecks in the network structure, whether due to the characteristics
of SMF or economical from a cost/return perspective. Besides, current access
networks based on SMF cable or RF connections are subject to interruptions
and should therefore be able to provide alternative transmission paths.
On the other hand, the expected increase in information traffic in the near
future leads to the establishment of new spectral allocation protocols for SMF.
The ITU-T G.989 standard thus emerges to promote next-generation (NGPON2)
networks that seek to exploit the spectrum available in SMFs through
point-to-multipoint Wavelength Division Multiplexing (WDM) networks as well
as in UDWDM (Ultra-Dense WDM) in a point to point configuration, addressed
to the end-user.
In this context, plastic optical fiber (POF) appears as an alternative
transmission medium to the SMF and promising in the short-range network.
The implementation of the POF extends to the telecommunications operators'
access network, the residential / building telecommunications network,
transport vehicles or the rapid re-establishment of communications in accidentprone
optical networks. Free Space Optical Transmission (FSO) is also a
promising means of communication and alternative for short-range RF or SMF
connections. FSO connections can be applied to the telecom operator's
access network, standby connections between GSM antennas, the connection
between an institution's buildings, point-to-multipoint wireless communications,
or the quick re-establishment of a cable optical device accidentally interrupted.
Thus, the POF and FSO transmission media will be studied here, exploring
new spectral limits and transmission capabilities involving GPON and NGPON2
network protocols. Coherent reception and data retrieval through
software-defined receivers for real-time digital signal processing will be
explored.<br>O aumento dos serviços prestados pelas operadoras de rede móvel, assim
como do tráfego nas redes-sem-fios (WiFi) têm explorado intensamente o
espectro de radiofrequência (RF) disponível. A rede fixa de telecomunicações
que conecta as antenas rádio, pontos de acesso WiFi ou outras tecnologias
(ex. Wimax), suporta novos serviços que exigem maiores taxas de
transmissão e conexões, como por exemplo a computação na nuvem, HDTV,
Internet das Coisas (IoT) ou a comunicações de Máquina-a-Máquina (M2M). A
fibra óptica monomodo em silício (SMF) tem sido a escolhida como o meio de
transporte de dados na rede fixa, uma vez que disponibiliza maiores larguras
de banda e taxas de transmissão.
Num contexto desejável de rede óptica ubíqua e transparente, subsistem
variados estrangulamentos na estrutura da rede, sejam devido às
características da SMF, sejam económicos numa perspectiva de
custo/retorno. Além disso, as actuais redes de acesso, baseadas em cabos de
SMF ou em ligações RF, estão sujeitas a interrupções e, portanto, devem
poder contemplar caminhos de transmissão alternativos.
Por outro lado, o aumento esperado no tráfego de informações no futuro
próximo leva ao estabelecimento de novos protocolos de alocação espectral
para a SMF. O padrão ITU-T G.989 surge, assim, para promover as redes de
próxima geração (NG-PON2) que procuram explorar o espectro disponível em
SMFs através de redes WDM (Wavelength Division Multiplexing) pontomultiponto,
bem como através de redes em UDWDM (Ultra-Dense WDM)
numa configuração ponto a ponto, endereçado ao utilizador final.
Neste contexto, a fibra óptica plástica (POF) surge como um meio de
transmissão alternativo à SMF e promissor na rede de curto alcance. A
implementação da POF estende-se à rede de acesso das operadoras de
telecomunicações, à rede de telecomunicações residencial/predial, aos
veículos de transporte ou no rápido restabelecimento das comunicações em
redes ópticas propensas a acidentes. A transmissão óptica de espaço livre
(FSO) também é um meio promissor de comunicação e uma alternativa nas
conexões em RF ou SMF de curto alcance. As conexões FSO podem ser
aplicadas à rede de acesso do operador de telecomunicações, às conexões
em reserva entre as antenas dos operadores móveis, à conexão entre os
edifícios de uma instituição, às comunicações sem fio ponto-multiponto ou no
rápido restabelecimento de um cabo óptico interrompido acidentalmente.
Assim, os meios de transmissão POF e FSO serão aqui estudados,
explorando-se novos limites espectrais e capacidades de transmissão
envolvendo os protocolos de redes GPON e NG-PON2. Serão exploradas a
recepção coerente e a recuperação de dados através de receptores definidos
por software, para o processamento de sinais digitais em tempo real.<br>Programa Doutoral em Engenharia Eletrotécnica
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Chew, Pei-Hsien, and 周沛賢. "52 m/9 Gb/s PAM4 Plastic Optical Fiber- Underwater Wireless Laser Transmission Convergence with a Laser Beam Reducer." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/7r7ytt.
Full textAbstract:
碩士<br>國立臺北科技大學<br>光電工程系<br>106<br>Underwater wireless laser transmission (UWLT), a promising provider of high-speed underwater links, has obtained considerable interest over the past few years. Some recent works have shown that high-speed UWLTs can be achieved over finite underwater links. Transmissions of several gigabit per second (Gb/s) with limited underwater links have been implemented using different water types with attenuation characteristics, which is a com-bination of absorption and scattering. Nevertheless, transmissions of several Gb/s with long-reach underwater links have not been realized. For the real implementation of high-speed
UWLTs, constructing a long-reach underwater link is amajor concern of system designers. Many applications of UWLTs have been proposed for environmental monitoring, disaster precaution, offshore exploration, and underwater oil pipe investigation. To meet the demands of different applications, a high-speed UWLT with a long-reach underwater link is required. A new transmissionmediumdifferent from the aquatic medium is required to realize a long-reach underwater link. A graded-index (GI) plastic optical fiber (POF) has been developed with good features, such as large core diameter, small bending radius, high bandwidthdistance product, and low transmission loss. The GI-POF can enhance the coverage of UWLT and, thus, can be effectively utilized as an underwater extender of UWLT. As a result, a long-reach underwater link can be practicably constructed by adopting a POF-UWLT convergence. In this Letter, a 9 Gb/s four-level pulse amplitude modulation (PAM4) POF-UWLTconvergence with a laser beam reducer for reducing the collimated beam diameter over a 50 m GI-POF transmission with a 2 m clear ocean water link is proposed.
For the first time, to the authors’ knowledge, a 52 m/9 Gb/s PAM4 POFUWLT convergence is practically demonstrated with the application of a laser beam reducer to reduce the collimated beam diameter. For reducing the collimated beam diameter, the laser beam reducer converts a large collimated beam diameter into a small one. The laser beam reducer has been adopted in free-space optical (FSO) communications to improve the performances of FSO links. However, it has not been adopted as the performance improvement scheme in POF-UWLT convergence. POF-UWLT convergence presents several similarities compared to FSO links due to the fact that they utilize optical wavelengths to deliver data signals between dedicated point-to-point links. A laser beam reducer, which can reduce the collimated beam diameter, is thereby expected to improve the performances of PAM4 POF-UWLT convergence. The performances of PAM4 POF-UWLT convergence in view of bit error rate (BER) and eye diagrams improve with the decrease of the collimated beam diameter because of the lower amounts of light absorbed by clear ocean water. Competent BER and clear eye diagrams (three independent eye diagrams) are acquired at a 50 m GI-POF operation with a 2 m clear ocean water link. Our novel proposal reveals a more prominent one than those of UWLTs with short-reach and low-speed characteristics. This proposed 52 m/9 Gb/s PAM4 POF-UWLT convergence is demonstrated to be superior over the prior UWLTs, given its feasibility for long-reach and high-speed underwater links.
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Lin, Che-wei, and 林哲緯. "Very high speed (>1Gb/s) visible LED applied for Plastic Optical Fiber communication and investigation of the internal carrier dynamic." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/56936800631218516412.
Full textAbstract:
碩士<br>國立中央大學<br>電機工程研究所<br>100<br>We demonstrate the performance of a novel cyan light-emitting diode (LED) on a patterned sapphire (PS) substrate as a light source for plastic optical fiber (POF) communications with the central wavelength at 500 nm. To further enhance the external quantum efficiency (EQE) and output power of this miniaturized high-speed LED, an LED with a PS substrate is adopted. Furthermore, by greatly reducing the number of active InxGa1-xN/GaN multiple quantum wells (MQWs) to three and minimizing the device active area, we can achieve a record high electrical-to-optical (E-O) bandwidth (as high as 400 MHz) among all the reported high-speed visible LEDs under a very-small DC bias current (40 mA). By use of the transistor out-line can (TO-can) package integrated with a lens (500 ?m diameter), a ~4 dB enhancement in coupled optical power from chip to POF and a measured power as high as -2.67 dBm under 40 mA bias current can be achieved.Very-high error-free 1.07 Gbps data transmission over a 50 m POF fiber has been successfully demonstrated using this device under a bias current of 40 mA with forward error correction (FEC) technique
The mechanism responsible for the efficiency droop in AlGaInP-based vertically structured red light-emitting diodes (LEDs) is investigated using dynamic measurement techniques.
Short electrical pulses ( 100 ps) are pumped into this device and the output optical pulses probed using high-speed photoreceiver circuits. From this, the internal carrier dynamic inside the device can be investigated by use of the measured electrical-to-optical (E-O) impulse responses. Results show that the E-O responses measured under different bias currents are all invariant from room temperature to 100 C. This is contrary to most results reported for AlGaInP-based red LEDs, which usually exhibit a shortening in the response time and degradation in output power with the increase of ambient temperature. According to the
extracted fall-time constants of the E-O impulse responses, the origin of the efficiency droop in our vertical LED structure, which has good heat-sinking, is not due to thermally induced carrier leakage, but rather should be attributed to defect recombination and the saturation of defect/spontaneous recombination processes under low and high bias current, respectively.
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Chen, Tom Chien-Sheng. "Scintillator wavelength influence in an optical dosimeter : Master of Medical Physics, Department of Physics and Astronomy, University of Canterbury, Christchurch, New Zealand /." 2006. http://library.canterbury.ac.nz/etd/adt-NZCU20060613.125721.
Full text
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Mai, Fei-jan, and 麥斐然. "Integration of LEDs and Plastic-Optical-Fibers for Automobile Headlamps Design." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/76235214032880382483.
Full textAbstract:
碩士<br>國立臺灣科技大學<br>電子工程系<br>98<br>A high-efficiency LED automobile headlamp is proposed and studied in this thesis. Using optical simulation software FRED, we design such LED module for automobile application. The research may divide into light-collecting system and light-projection system. During simulation, the diameter of plastic optical fiber is 10 mm and is used to link LEDs and either system. Thus, LEDs could get avoid of serious heat-dissipation problem by putting LEDs far away from the vehicle engine. First of all, we select appropriate LEDs and plastic optical fiber to build up the simulation models. For the light-collecting system, complex optical components for light coupling are unnecessary. We use geometric optics to design the elliptical reflector. The diameter of LED is 2.5 mm and plastic fiber has numerical aperture of 0.55. A maximum coupling efficiency of 94.7% is obtained. The average coupling efficiency is distributed from 74.1% for 2 LEDs to 48.2% for 7 LEDs.
For the projection system issue, two different designs are proposed. The first one is fiber-shield using an elliptic reflector integrated a shield to create the desired shape. Its projection efficiency is around 54%. Although has drawback as light source be blocked by the shield. Nevertheless, one may switch the shield for different purposes. The second one is fiber-waveguide which makes the cross-section shape match standard light pattern and high projection efficiency up to 70% is obtained. It has the merits to increase the uniformity of light pattern and to reduce the glare without lose much power. It also could effectively reduce the headlamp size. Both these simulation works are done using optical software OSLO. Either design can make the light projection completely. In final, we also integrate light-collecting system and projection system for simulation. The light pattern shows clearly that the cut-off line is 25 m away with 15 degrees boost up on the right-hand side, and the illuminance of at test point fits the criteria of ECE R112.
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Chang, Kuang-yao, and 張光耀. "Enhancement of Coupling Efficiency of Plastic Optical Fibers with Different End Shapes." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/00231799410875227571.
Full textAbstract:
碩士<br>國立中山大學<br>機械與機電工程學系研究所<br>94<br>The fiber-optics communication device with a plastic optical fiber (POF) has become a technology of increasing interests. The attenuation of commercial available POF has been improved to tens of decibels per kilometer. Due to its flexibility and high alignment efficiency, it has been widely used in many areas.
In this study, different end shapes of POF have been proposed to increase the coupling efficiency of a POF from a surface emitting LED. Both the experiments and a ray tracing simulation are performed to investigate the coupling scheme. Experimental results also illustrate the feasibility of using ray tracing model in POF end shapes design.
The effect of ball fiber lens on coupling efficiency is studied first. Lens material is EPO-TEK 353ND two parts epoxy. The result indicates that the ball fiber lens can improve the coupling efficiency significantly. A more impact end shape modified from the ball fiber lens is proposed in this study, i.e. a thin tip-rounded fiber lens. Numerical and experimental results show the tip can work as good as a ball fiber lens does. A reflection-styled end shape has also been proposed in this thesis, i.e. a taper-ended POF. In this design, the taper edge serves as a reflector to bend the rays incident on it by total internal reflection. The maximum efficiency achieves a great improvement from the previous design.
Further study on the various fiber types with different sizes and numerical apertures have also been studied by the ray tracing model.
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He, Hui-Ling, and 何惠鈴. "A Study of Luminous Home Textiles by Plastic Optical Fibers and combining LED into Weaving Fabric Design." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/75648803904704139745.
Full textAbstract:
碩士<br>樹德科技大學<br>應用設計研究所<br>97<br>As technology advances, it can be expected that electronic technology will be better integrated with textiles and clothes in future life. Hence, the perfect integration between electric and electronic hardware and soft textiles will become the major trend for research and development in the field of textile research in the future. This study primarily aims to develop the technology to produce luminous woven fabrics for home textiles through the integration with LED and plastic optical fibers (POF).
The experiment data was applied for the investigation on the textile technologies related to the integration with LED and plastic optical fibers: 1) The methods with regard to combine LED with conductive yarn were investigated, in order to understand how LED is incorporated into the textile technologies; 2) The brightness of sidewise-scattered light was enhanced by cutting the surface of plastic optical fibers, thereby investigating the optimal cutting frequency and angle; 3) After a 40cm-long plastic optical fiber bundle has undergone surface cutting, the influence of lighting methods and distance on the brightness of sidewise-scattered light was tested with lighting from either one end or both ends; 4) The plastic optical fibers that have undergone surface cutting were stretched, to understand the changes in the tensile strength of plastic optical fibers that have undergone a cutting process.
Based on the experiment results, the following results have been obtained:
(1) The optimal method to combine LED with conductive yarn is to use graphite conductive adhesive to bind the positive and negative poles of LED and conductive yarn in a parallel direction.
(2) According to the experiment results, the brightness of sidewise-scattered light of plastic optical fibers that have undergone surface cutting is enhanced. Compared with an angle of 90°, a cutting angle of 45° enables a higher level of brightness.
(3) From the test on the brightness of sidewise-scattered light of the 40cm-long plastic optical fiber bundle, in comparison between lighting from one end and from both ends at the same part of the fiber, the brightness of sidewise-scattered light from both ends is comparatively high.
(4) According to the results from the tensile strength test of plastic optical fibers, it can be learned that as long as there is a cut on the surface of plastic optical fibers, the tensile strength dramatically decreases, regardless of cutting angles or frequencies. Therefore, integrating plastic optical fibers that have been cut with fabrics in a latitudinal direction will be a better choice.
Based on the experiment results, to integrate LED with conductive yarn, we just use conductive graphite adhesive to bind LED and conductive yarn in a parallel direction. As a result, we may first weave a large quantity of conductive yarns, and then use conductive graphite adhesive to integrate LED with luminous yarns. In other words, LED luminous yarns may be put into mass production in the future. The brightness of plastic optical fibers that have undergone surface cutting is indeed enhanced. The experiment results suggest the optimal cutting frequencies for plastic optical fibers of different specifications as reference for future researches.
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Lai, Yao-Zih, and 賴耀梓. "Development of a Lightweight Portable Optical Measurement System for the Print-Through Phenomenon of Fiber-Reinforced Plastics (FRP)." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/23635513292372686780.
Full textAbstract:
碩士<br>國立臺灣科技大學<br>機械工程系<br>98<br>The objective of the study is to develop a lightweight portable optical measurement system for the print-through phenomenon of fiber-reinforced plastics. In the developed system, a parallel laser beam, generated from a fan-shaped micro-focused laser passing a collimating lens, was projected onto the test object. The reflected image projected on a screen was captured by a CCD camera connected to a notebook computer to analyze the print-through phenomenon (PTP) and the surface roughness of a test object. Two indexes, namely the profile peak-valley height and wave-height of the Fast-Fourier Transform based on the centerline of the extracted image profile, were proposed to quantify the PTP of a test specimen. The mean line width of the extracted image was applied to evaluate the surface roughness of a test specimen, based on the scattering theorem. A set of software programmed with Borland C++ Builder language was developed to calculate the proposed indexes and the mean line width. According to the verification results, the systematic error for the profile measurement of the newly developed system using the threshold value of 100 is about 1.17 μm. Four grades for the PTP evaluated by the proposed index - the profile peak-valley height, namely excellent, OK, with PTP, serious PTP, were proposed in this study, according to the experts’ experiences. The developed measurement system has been taken to some yacht factories to do the on-site measurements. The measurement results were, in general, consistent with the surface conditions of the polished surfaces.
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Wu, Bing-Chi, and 吳秉錡. "Investigations of the Influence of Processing Conditions on the Transmission Loss Properties of Step-Index Plastic Optical Fibers." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/52097398870042938162.
Full textAbstract:
碩士<br>國立臺灣科技大學<br>高分子工程系<br>94<br>In this study, we discussed the rheologic properties of poly carbonate(PC)、poly methyl methacrylate(PMMA)、poly styrene(PS) and ARTON、TOPAS and ZEONEX of metallocene cyclic olefin copolymer(MCOC) series as core material and fluoro copolymer(THV) as cladding material making plastic optical fiber at first. Then according to the data measured by rheometer, we got the correlation suitable for complex fiber-spinning machine after calculation from formula. Furthermore, we investigated the relationship of transmission loss and core/cladding shear viscosity under the optimization of processing. The result shows the minimum of transmission loss corresponding different core/cladding shear viscosity with different core material. In order to understand the behavior of plastic optical fiber, their ultra-red, ultraviolet and visible light absorption spectrum, haze and the cross-section morphology were also discussed further.
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Chan, Chi-meng, and 詹啟孟. "Development of a Portable Optical Measurement System for the Surface Characteristics of a Yacht-used Fiber-Reinforced Plastics (FRP)." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/72043678630521008657.
Full textAbstract:
碩士<br>國立臺灣科技大學<br>機械工程系<br>97<br>The objective of the study is to develop a portable optical measurement system for the surface characteristics, including the surface roughness, profile, and the print-through phenomenon (PTP), for the yacht-used fiber-reinforced plastics (FRP). The developed system mainly consists of a micro-focused fan-shaped laser as a fringe projector, a focus lens, a CCD Camera, a measurement box body with a screen for the reflected fringe, a notebook PC, and a set of developed measurement software. The measurement length of the focused parallel beam is 43 mm. Appling a 1mW laser as a fringe projector to measure the flat specimens, and use of the indexes of image profile peak-valley height and average line width to evaluate the surface roughness value (Rmax) of the test specimens, the average system deviations were 34.15％ and 25.4％, respectively. Appling a 5mW laser as a fringe projector to measure the local smoothed 2D specimens, and use of the index of curve average line width to estimate the Rmax and Ra, the average system deviation were 6.25％ and 1.7 ％, respectively. Using a 5mW laser as a fringe projector to measure the local profile of a 2D smooth specimen, compared with the contact contour profile measuring system, a transformation factor of 56.57 for profile calibration was obtained. The maximum profile deviation was about + 2.72μm based on the calibration results. Using the curve peak-valley height index and the curve average line width index to estimate the surface roughness value (Rmax) of the curved specimens, the average system deviations were 6.25％ and 1.7％, respectively. Using fast Fourier transform (FFT) method to estimate the PTP of the test specimens, the more obvious the PTP, the larger the magnitude of FFT, based on the analysis results.
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Ospald, Felix. "Contributions to the Simulation and Optimization of the Manufacturing Process and the Mechanical Properties of Short Fiber-Reinforced Plastic Parts." 2019. https://monarch.qucosa.de/id/qucosa%3A36522.
Full textAbstract:
This thesis addresses issues related to the simulation and optimization of the injection molding of short fiber-reinforced plastics (SFRPs).
The injection molding process is modeled by a two phase flow problem.
The simulation of the two phase flow is accompanied by the solution of the Folgar-Tucker equation (FTE) for the simulation of the moments of fiber orientation densities.
The FTE requires the solution of the so called 'closure problem'', i.e. the representation of the 4th order moments in terms of the 2nd order moments.
In the absence of fiber-fiber interactions and isotropic initial fiber density, the FTE admits an analytical solution in terms of elliptic integrals.
From these elliptic integrals, the closure problem can be solved by a simple numerical inversion.
Part of this work derives approximate inverses and analytical inverses for special cases of fiber orientation densities.
Furthermore a method is presented to generate rational functions for the computation of arbitrary moments in terms of the 2nd order closure parameters.
Another part of this work treats the determination of effective material properties for SFRPs by the use of FFT-based homogenization methods.
For these methods a novel discretization scheme, the 'staggered grid'' method, was developed and successfully tested. Furthermore the so called 'composite voxel'' approach was extended to nonlinear elasticity, which improves the approximation of material properties at the interfaces and allows the reduction of the model order by several magnitudes compared to classical approaches. Related the homogenization we investigate optimal experimental designs to robustly determine effective elastic properties of SFRPs with the least number of computer simulations.
Finally we deal with the topology optimization of injection molded parts, by extending classical SIMP-based topology optimization with an approximate model for the fiber orientations.
Along with the compliance minimization by topology optimization we also present a simple shape optimization method for compensation of part warpage for an black-box production process.:Acknowledgments v
Abstract vii
Chapter 1. Introduction 1
1.1 Motivation 1
1.2 Nomenclature 3
Chapter 2. Numerical simulation of SFRP injection molding 5
2.1 Introduction 5
2.2 Injection molding technology 5
2.3 Process simulation 6
2.4 Governing equations 8
2.5 Numerical implementation 18
2.6 Numerical examples 25
2.7 Conclusions and outlook 27
Chapter 3. Numerical and analytical methods for the exact closure of the Folgar-Tucker equation 35
3.1 Introduction 35
3.2 The ACG as solution of Jeffery's equation 35
3.3 The exact closure 36
3.4 Carlson-type elliptic integrals 37
3.5 Inversion of R_D-system 40
3.6 Moment tensors of the angular central Gaussian distribution on the n-sphere 49
3.7 Experimental evidence for ACG distribution hypothesis 54
3.8 Conclusions and outlook 60
Chapter 4. Homogenization of SFRP materials 63
4.1 Introduction 63
4.2 Microscopic and macroscopic model of SFRP materials 63
4.3 Effective linear elastic properties 65
4.4 The staggered grid method 68
4.5 Model order reduction by composite voxels 80
4.6 Optimal experimental design for parameter identification 93
Chapter 5. Optimization of parts produced by SFRP injection molding 103
5.1 Topology optimization 103
5.2 Warpage compensation 110
Chapter 6. Conclusions and perspectives 115
Appendix A. Appendix 117
A.1 Evaluation of R_D in Python 117
A.2 Approximate inverse for R_D in Python 117
A.3 Inversion of R_D using Newton's/Halley's method in Python 117
A.4 Inversion of R_D using fixed point method in Python 119
A.5 Moment computation using SymPy 120
A.6 Fiber collision test 122
A.7 OED calculation of the weighting matrix 123
A.8 OED Jacobian of objective and constraints 123
Appendix B. Theses 125
Bibliography 127<br>Diese Arbeit befasst sich mit Fragen der Simulation und Optimierung des Spritzgießens von kurzfaserverstärkten Kunststoffen (SFRPs).
Der Spritzgussprozess wird durch ein Zweiphasen-Fließproblem modelliert.
Die Simulation des Zweiphasenflusses wird von der Lösung der Folgar-Tucker-Gleichung (FTE) zur Simulation der Momente der Faserorientierungsdichten begleitet.
Die FTE erfordert die Lösung des sogenannten 'Abschlussproblems'', d. h. die Darstellung der Momente 4. Ordnung in Form der Momente 2. Ordnung.
In Abwesenheit von Faser-Faser-Wechselwirkungen und anfänglich isotroper Faserdichte lässt die FTE eine analytische Lösung durch elliptische Integrale zu.
Aus diesen elliptischen Integralen kann das Abschlussproblem durch eine einfache numerische Inversion gelöst werden.
Ein Teil dieser Arbeit leitet approximative Inverse und analytische Inverse für spezielle Fälle von Faserorientierungsdichten her.
Weiterhin wird eine Methode vorgestellt, um rationale Funktionen für die Berechnung beliebiger Momente in Bezug auf die Abschlussparameter 2. Ordnung zu generieren.
Ein weiterer Teil dieser Arbeit befasst sich mit der Bestimmung effektiver Materialeigenschaften für SFRPs durch FFT-basierte Homogenisierungsmethoden.
Für diese Methoden wurde ein neuartiges Diskretisierungsschema 'staggerd grid'' entwickelt und erfolgreich getestet. Darüber hinaus wurde der sogenannte 'composite voxel''-Ansatz auf die nichtlineare Elastizität ausgedehnt, was die Approximation der Materialeigenschaften an den Grenzflächen verbessert und die Reduzierung der Modellordnung um mehrere Größenordnungen im Vergleich zu klassischen Ansätzen ermöglicht. Im Zusammenhang mit der Homogenisierung untersuchen wir optimale experimentelle Designs, um die effektiven elastischen Eigenschaften von SFRPs mit der geringsten Anzahl von Computersimulationen zuverlässig zu bestimmen.
Schließlich beschäftigen wir uns mit der Topologieoptimierung von Spritzgussteilen, indem wir die klassische SIMP-basierte Topologieoptimierung um ein Näherungsmodell für die Faserorientierungen erweitern.
Neben der Compliance-Minimierung durch Topologieoptimierung stellen wir eine einfache Formoptimierungsmethode zur Kompensation von Teileverzug für einen Black-Box-Produktionsprozess vor.:Acknowledgments v
Abstract vii
Chapter 1. Introduction 1
1.1 Motivation 1
1.2 Nomenclature 3
Chapter 2. Numerical simulation of SFRP injection molding 5
2.1 Introduction 5
2.2 Injection molding technology 5
2.3 Process simulation 6
2.4 Governing equations 8
2.5 Numerical implementation 18
2.6 Numerical examples 25
2.7 Conclusions and outlook 27
Chapter 3. Numerical and analytical methods for the exact closure of the Folgar-Tucker equation 35
3.1 Introduction 35
3.2 The ACG as solution of Jeffery's equation 35
3.3 The exact closure 36
3.4 Carlson-type elliptic integrals 37
3.5 Inversion of R_D-system 40
3.6 Moment tensors of the angular central Gaussian distribution on the n-sphere 49
3.7 Experimental evidence for ACG distribution hypothesis 54
3.8 Conclusions and outlook 60
Chapter 4. Homogenization of SFRP materials 63
4.1 Introduction 63
4.2 Microscopic and macroscopic model of SFRP materials 63
4.3 Effective linear elastic properties 65
4.4 The staggered grid method 68
4.5 Model order reduction by composite voxels 80
4.6 Optimal experimental design for parameter identification 93
Chapter 5. Optimization of parts produced by SFRP injection molding 103
5.1 Topology optimization 103
5.2 Warpage compensation 110
Chapter 6. Conclusions and perspectives 115
Appendix A. Appendix 117
A.1 Evaluation of R_D in Python 117
A.2 Approximate inverse for R_D in Python 117
A.3 Inversion of R_D using Newton's/Halley's method in Python 117
A.4 Inversion of R_D using fixed point method in Python 119
A.5 Moment computation using SymPy 120
A.6 Fiber collision test 122
A.7 OED calculation of the weighting matrix 123
A.8 OED Jacobian of objective and constraints 123
Appendix B. Theses 125
Bibliography 127
48
Frias, Ana Rita da Silva Rocha. "High performance luminescent solar concentrators for flexible waveguiding photovoltaics." Doctoral thesis, 2019. http://hdl.handle.net/10773/29231.
Full textAbstract:
The mismatch between the AM1.5G spectrum and photovoltaic cell absorption is one of the critical factors limiting their performance. To overcome it, several approaches have been proposed. Among them, emphasis is given to luminescent down-shifting layers, additive devices that are able to enhance performance under typical operation conditions, and to luminescent solar concentrators, a complementary technology to PV cells for use in urban environments.
Luminescent down-shifting layers are coatings that are directly deposited on the surface of photovoltaic cells, and absorb the incident radiation that is not absorbed by photovoltaic cells, subsequently re-emitting it at a specific wavelength and refracting/reflecting it towards the photovoltaic cell. Luminescent solar concentrators are devices comprising a transparent matrix incorporating optically active centres that absorb the incident radiation, which is then re-emitted at a specific wavelength and transferred by total internal reflection to photovoltaic cells located at the edges of the matrix. This configuration enables photovoltaic devices to be embedded in building facades or windows, allowing them to be transformed into energy harvesting units, contributing for the development of zero-energy buildings.
This thesis aimed to produce and characterize transparent organic- inorganic hybrids with controlled thickness and refractive index using poly(methyl methacrylate), di- and triureasils incorporating different lanthanide ions, namely Tb3+, Eu3+, Y b3+ and Nd3+, and the fol- lowing organic dyes: Rhodamine 6G and Rhodamine 800, silicon 2,3- naphthalocyaninebis(trihexylsilyloxide), chlorophyll and R- phycoerythrin molecules with emission tuned from the visible to NIR spectral regions. LSCs with planar and cylindrical geometry are studied. The use of the cylindrical geometry allows the effect of concentration to be higher when compared with the planar geometry, since the ratio between the exposed area and the area of the edges is increased. The cylindrical geometry concentrators are produced from plastic optical fibres with hollow cores, where the optically active layer was injected. The exposed area was further optimised through the production of bundles of LSCs, in which optical fibres with different cladding geometries were placed side by side. Finally, the attractive properties of natural-based dye molecules for the production of luminescent solar concentrators, which have been poorly explored, are also studied through the incorporation of chlorophyll and R- phycoerythrin as optically active centres. Key experimental results were also validated using Monte-Carlo ray-tracing simulations.<br>O desfasamento entre o espetro AM1.5G e o espetro de absorção das células fotovoltaicas é um fator crítico que limita o desempenho das mesmas. De forma a ultrapassar isto, diversas aproximações têm sido propostas. Entre elas, têm sido enfatizadas as camadas luminescentes por desvio descendente de energia, dispositivos capazes de melhorar o desempenho em condições de operação específicas, e os concentradores solares luminescentes, considerados uma tecnologia complementar a das células fotovoltaicas para utilização em ambientes urbanos.
As camadas luminescentes por desvio descendente de energia são revestimentos diretamente depositados no topo de células fotovoltaicas capazes de absorver a radiação incidente complementar à que as células fotovoltaicas absorvem e subsequentemente reemitem-na com um comprimento de onda específico que é refratado/refletido até à célula fotovoltaica. Os concentradores solares são dispositivos compostos por uma matriz transparente incorporando centros óticos ativos que absorbem a radiação incidente, que é posteriormente reemitida com um comprimento de onda específico e transportada por reflexão interna total até à célula fotovoltaica localizada nas extremidades da matriz. Esta configuração permite a produção de dispositivos fotovoltaicos embebidos em fachadas de edifícios e janelas, permitindo que estes sejam transformados em unidades de produção de energia, contribuindo para o desenvolvimento de edifícios de energia zero.
O principal objetivo deste trabalho consiste no fabrico e caracterização de híbridos orgânicos-inorgânicos com espessura e índice de refração controlados utilizando polimetil-metacrilato, di- e tri-ureasil incorporando diferentes iões lantanídeos, nomeadamente Tb3+, Eu3+, Yb3+ and Nd3+, e corantes orgânicos como Rodamina 6G, Rodamina 800, Silício 2,3-naftalocianina bis(trietil siloxano), clorofila e R-ficoeritrina cuja emissão varia entre o visível e o infravermelho próximo. Concentradores solares luminescentes com geometria planares e cilíndrica foram estudados. A geometria cilíndrica permite que o efeito de concentração seja superior, quando comparado com a geometria planar, uma vez que a razão entre a área exposta e a área das extremidades aumenta. A geometria cilíndrica é explorada, através da produção de concentradores solares luminescentes em fibra ótica de plástico onde a camada ótica ativa se encontra no interior da fibra, como um preenchimento do núcleo oco. A possibilidade de aumentar a área exposta foi, também, abordada através do fabrico de uma matriz de concentradores solares luminescentes colocados lado a lado com diferentes geometrias da bainha. Para além disso, as propriedades óticas dos corantes orgânicos naturais, que têm sido pouco exploradas na literatura, foram alvo de estudo através da incorporação de moléculas de clorofila e de R-ficoeritrina como centros óticos em concentradores solares luminescentes. Os resultados experimentais mais relevantes foram validados através de simulações baseadas no método de Monte-Carlo.<br>Programa Doutoral em Física