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Sarangan, Andrew M. "Multi-wavelength distributed feedback lasers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq21388.pdf.
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Tsang, Chi Foon. "Dynamics of distributed feedback lasers." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320037.
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Morrison, Gordon. "Modelling the spectra of distributed feedback lasers /." *McMaster only, 2002.
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Khan, Nusrallah. "Experimental studies of distributed feedback dye lasers." Thesis, University of Essex, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302848.
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Lusty, Michael E. "Temporal and frequency characteristics of distributed feedback dye lasers." Thesis, University of St Andrews, 1989. http://hdl.handle.net/10023/14312.
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Previous studies of distributed feedback dye lasers (DFDL's) have identified that the linewidth of the device scales, to a first approximation, with the level of pumping employed. A more recent development is that the DFDL can be used to produce single ultrashort pulses. To produce such pulses the main requirement is that the laser is operated close to its threshold. An apparent contradiction exists here since, by lowering the pump power to achieve narrow linewidth operation, the near threshold region must be avoided since pulsing operation acts to increase the linewidth (to at least the Fourier transform of the pulse duration). This thesis further investigates the mechanisms which contribute to the temporal and linewidth properties of the laser. It is identified that by judicious choice of operating conditions a regime exists where the DFDL may be operated with a linewidth approaching that of the transform limit for the nanosecond pulse durations involved. After introducing the different types of distributed feedback lasers the thesis first reviews previously understood DFDL behaviour. Different DFDL geometries are considered with a view to their particular temporal and linewidth properties. A strategy for the development of a narrow linewidth DFDL is presented. The experimental laser system is described detailing the operation and characteristics of the frequency doubled Q switched Nd:YAG pump laser and the two different DFDL geometries. A high resolution computer aided interferometry (CAIN) system is described which provided single shot linewidth measurements. This system was used extensively in the experiments reported. DFDL linewidth is seen to depend on the thermo-optical properties of the dye's host solvent and as such a full characterization of commonly used solvents is presented. The temporal behaviour of the laser is considered theoretically with the aid of a coupled rate equation model which describes the interplay between the population inversion and the cavity photon flux. The model is used to predict short (picosecond) and smooth (nanosecond) pulse operation of the laser. Finally, a description of and the results obtained from various experimental investigations into the DFDL are presented. Temporal analysis, using a streak camera, revealed that, as expected, under certain circumstances multiple pulsing of picosecond duration could occur. Different conditions however, lead to narrow linewidth (~100 MHz) operation. A description of the two operating regimes is presented and these are related to the particular parameters involved e.g. the grating length or the level of pumping employed.
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Riechel, Stefan. "Organic semiconductor lasers with two-dimensional distributed feedback." Diss., [S.l.] : [s.n.], 2002. http://edoc.ub.uni-muenchen.de/archive/00000172.
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Clifton, Brandon M. "Study of experimental gain-switched distributed feedback lasers /." Available to subscribers only, 2005. http://proquest.umi.com/pqdweb?did=1079666511&sid=11&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Kasunic, Keith John 1957. "Nonlinear optics of circular-grating distributed-feedback semiconductor lasers." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/282487.
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This dissertation investigates the nonlinear optics of circular-grating distributed-feedback (CGDFB) semiconductor lasers. Included are gain saturation, index saturation, and self- and cross-phase modulation third-order nonlinearities. After a brief review of the historical and technical background needed to understand our results, a numerical model is developed for gain saturation. This model includes a radially-varying nonlinear gain and a uniformly-distributed grating loss in the solution of the coupled-mode equations. The results show that lossy, high-power operation results in an optimum coupling strength for efficient conversion of pump power into useful output pourer. Results also show a multi-mode spectrum for large coupling strengths, a consequence of mode selection governed by a spatially-varying gain distribution. Single-mode selection entails operating at approximately the optimum coupling coefficient determined for efficient pumping. These results are extended by including the gain/index coupling described by the linewidth enhancement factor. A unique feature of this coupling is the possibility of above-threshold, single-mode operation over a limited power range, even for the case of large coupling coefficients. Similar results are obtained for the circular-grating distributed-Bragg-reflector (CGDBR) laser. The excess spontaneous emission rate associated with the nonuniform CGDFB radial (longitudinal) field profiles is also calculated. The resulting above-threshold linewidth closely follows the inverse-power dependence predicted by the Schawlow-Townes relation. To include third-order nonlinearities, we derive coupled-mode equations which describe self- and cross-phase modulation effects via an intensity-dependent refractive index. It is then shown that the circular-grating structure acts as an all-optical switch. We also find that an additional pi/2 phase shift at the center of the grating permits the possibility of self-pulsing cylindrical gap solitons. For a positive nonlinearity (n2 it is shown numerically that these solitons are not physically allowable. That is, for a passive structure, time-dependent self-pulsing behavior is damped by the 1/beta r factor in the self- and cross-phase modulation terms. This damping can be compensated for by the addition of gain. In this case, self-pulsing with an excellent contrast ratio is obtained. The numerical methods used to obtain both steady-state and time-dependent solutions are also described. The steady-state results are obtained using a multi-dimensional Newton-Raphson technique known as the "shooting" method. Time-dependent data use a fourth-order predictor-corrector technique. The stability of the time-dependent solutions to the exact coupled-mode equations is reviewed. Coupled-mode equations based on a large-radius approximation for the Hankel functions are found to be stable over a wider range of variables. Numerical tests used to verify the time-dependent software are described.
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Saxena, Bhavaye. "Noise Characteristics for Random Fiber Lasers with Rayleigh Distributed Feedback." Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31766.
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Frequency and intensity noise are characterized for Erbium-Doped Fiber and Brillouin random lasers based on Rayleigh distributed feedback mechanism. We propose a theoretical model for the frequency noise of an Er-doped fiber random lasers using the property of random phase modulations from multiple scattering points in ultra-long fibers. We find that the Rayleigh feedback suppresses the noise at higher frequencies by introducing a Lorentzian envelope over the thermal frequency noise of a long fiber cavity. The theoretical model and measured frequency noise agree quantitatively with two fitting parameters. A similar model, which also includes additional acoustic fluctuations and a distributed gain profile in the fiber, has been speculated for the Brillouin random laser. These random laser exhibits a frequency noise level of < 6 Hz^2/Hz at 2 kHz, which is lower than what is found in conventional narrow-linewidth EDF fiber lasers and Nonplanar Ring Laser oscillators (NPRO) by a factor of 166 and 2 respectively.
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Lei, Hongchi. "GaAs-based distributed feedback lasers based on GaAs-InGaP regrowth technology." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/18162/.
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This thesis describes the conceptualisation and realisation of GaAs-based self-aligned stripe (SAS) distributed feedback lasers (DFB) based on GaAs-InGaP regrowth technology, and its incorporation into the development of master oscillator power amplifier (MOPA) photonic integrated circuit (PIC). GaAs-based SAS DFB lasers operate via a single longitudinal mode and provide a robust, portable and low cost solution to enable a broad range of potential applications. Compared to other waveguides, e.g. ridge waveguide, SAS structures enable narrower active regions and demonstrate better characteristics with a lower sensitivity to temperature. In my designs, InGaP/GaAs buried gratings are formed utilising an Al-free grating sequence GaAs-InGaP-GaAs, whilst the SAS waveguides are realised via a stripe-etched n-doped InGaP optoelectronic confinement layer, where no AlGaAs is exposed during the fabrication process. Chapter 1 goes through the development of DFB lasers over almost 5 decades since its birth in 1970s, followed by discussion of the gap between present GaAs-based PIC technologies and their commercialisation. After, Chapter 2 introduces the experimental methodology involved in the research activities conducted: fundamental principles of DFB lasers and the 4-stage research process. The following 3 chapters describe the 3 main projects in this research. Chapter 3 begins with the design of 2×, 4× and 6× InGaAs QWs narrow ridge DFB lasers in, and then moved onto the conceptualisation and realisation of 2× and 4× InGaAs QWs SAS DFB lasers in Chapter 4. This SAS-DFB technology was then applied to the development of monolithically integrated 4× InGaAs QWs MOPA PIC in Chapter 5. In Chapter 6, I outline some future work to be conducted for further achievement. An optimised design of SAS-DFB-MOPA is first discussed. I then present some preparatory works for two other potential future directions: widely tunable GaAs-based sampled grating distributed Bragg reflector laser (SG-DBR) and high power ~1180nm In(Ga)As/GaAs DWELL (dot-in-a-well) SAS-DFB-MOPA.
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Das, Bijoy Krishna. "Integrated optical distributed Bragg reflector and distributed feedback lasers in Er:LiNbO3 waveguides with photorefractive gratings." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969348541.
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Sundaresan, H. "The development of narrow linewidth, tunable lasers operating at 1.55#mu#m." Thesis, University of Sheffield, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390890.
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Dridi, Kais. "Semiconductor Corrugated Ridge Waveguide Distributed Feedback Lasers: Experimental Characterization and Design Considerations." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32327.
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Semiconductor corrugated ridge waveguide (CRW) distributed feedback (DFB) lasers offer compelling advantages over standard DFB lasers. Indeed, the use of surface gratings etched on the ridge waveguide sidewalls in CRW-DFB devices avoids any epitaxial overgrowth. This provides a considerable simplification in the fabrication process, reducing cost and time of manufacturing, and ultimately increasing yield. It offers also the potential for monolithic integration with other devices, paving the way towards low-cost and mass-production of photonics integrated circuits. In recent years, the re-consideration of growth-free DFB lasers has drawn considerable attention, particularly with the current state-of-the-art photolithography machines. In this work, we present an experimental investigation on two generations of InGaAsP/InP multiple-quantum-well (MQW) CRW-DFB lasers that have been fabricated using stepper lithography. An early developed 1310 nm CRW-DFB laser showed stable single mode with high side-mode suppression ratios (SMSR) (>50 dB), albeit with thresholds higher than anticipated. A subsequent single-mode 1550 nm CRW-DFB laser showed stable operation with SMSR (>50 dB) and narrow spectral linewidths (≤250 kHz), observed for a wide range of current injection. Besides, novel multi-electrode CRW-DFB lasers have been tested. The experimental investigation showed that narrower linewidth (<150 kHz) and wide wavelength tunability (>3 nm) have been recorded using different multi-electrode current injection configurations.
The application of a time-domain modeling approach for semiconductor CRW-DFB lasers is then described for the first time. We numerically studied the effect of the radiation modes on CRW-DFB laser properties by using time-domain coupled wave equations. High-order corrugated gratings with λ/4 phase-shit were analyzed, where the degree of longitudinal spatial hole burning (LSHB) can be effectively reduced by means of fine tuning of the grating duty cycle. Additionally, we showed how the side-mode suppression ratio can be predicted depending on the device geometry.
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Richardson, Scott. "The fabrication and lithography of conjugated polymer distributed feedback lasers and development of their applications." Thesis, St Andrews, 2007. http://hdl.handle.net/10023/401.
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Shen, Yangfei. "Coupled Wave Analysis of Two-Dimensional Second Order Surface-Emitting Distributed Feedback Lasers." University of Dayton / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1461713975.
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Das, Bijoy Krishna [Verfasser]. "Integrated Optical Distributed Bragg Reflector and Distributed Feedback Lasers in Er:LiNbO3 Waveguides with Photorefractive Gratings / Bijoy Krishna Das." Aachen : Shaker, 2003. http://d-nb.info/1179039815/34.
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Yelen, Kuthan. "Design method for ultimate efficiency in linear-cavity continuous-wave lasers using distributed-feedback." Thesis, University of Southampton, 2004. https://eprints.soton.ac.uk/15463/.
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A novel analytical method for the design of linear-cavity continuous-wave laser cavitiesthat guarantees the ultimate efficiency is developed, theoretically studied and experimentally verified. Opposed to the earlier methods, which optimise the parameters of a priori defined cavity, the developed method derives the cavity analytically based on the active medium properties for the chosen pumping scheme. The method combines the general grating design equations, valid for both passive and active media, and the optimum signal power calculations. The idea that lies at the heart of the design method is to sustain the optimum signal power at every single point in the entire cavity byemploying distributed-feedback for the maximum local, as a result, for the maximum overall conversion efficiency. Theoretical study starts with the critical investigation of the previous optimisation approaches. After addressing the limitations of these approaches, it is shown how toimprove the efficiency further than the parametric optimisation using intuitive arguments based on the effective cavity length and optimum reflectivities in DFB lasers. The critical importance of the signal distribution is highlighted, and following this observation the grating design method for arbitrary signal distributions is developed. The concept of optimum signal power is introduced and the spatial unfolding of the optimum values is illustrated. Boundary conditions, grating production limitations and effects of modelling parameters are addressed. Modal stability of the new designs is investigated. A novel approach to the simulation of Er/Yb co-doped fibre lasers is presented with experimental justification. Accurate laser characteristics are predicted for different designs, including the ultimate efficiency designs. Theoretical studies are verified with experimental data in Er/Yb co-doped fibre and discussions are extended to Yb doped fibres, high pump powers and alternative pumping schemes.
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Blanchard, Romain. "Fourier optics for wavefront engineering and wavelength control of lasers." Thesis, Harvard University, 2013. http://dissertations.umi.com/gsas.harvard:11216.
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Since their initial demonstration in 1994, quantum cascade lasers (QCLs) have become prominent sources of mid-infrared radiation. Over the years, a large scientific and engineering effort has led to a dramatic improvement in their efficiency and power output, with continuous wave operation at room temperature and Watt-level output power now standard. However, beyond this progress, new functionalities and capabilities need to be added to this compact source to enable its integration into consumer-ready systems. Two main areas of development are particularly relevant from an application standpoint and were pursued during the course of this thesis: wavelength control and wavefront engineering of QCLs. The first research direction, wavelength control, is mainly driven by spectroscopic applications of QCLs, such as trace gas sensing, process monitoring or explosive detection. We demonstrated three different capabilities, corresponding to different potential spectroscopic measurement techniques: widely tunable single longitudinal mode lasing, simultaneous lasing on multiple well-defined longitudinal modes, and simultaneous lasing over a broad and continuous range of the spectrum. The second research direction, wavefront engineering of QCLs, i.e. the improvement of their beam quality, is relevant for applications necessitating transmission of the QCL output over a large distance, for example for remote sensing or military countermeasures. To address this issue, we developed plasmonic lenses directly integrated on the facets of QCLs. The plasmonic structures designed are analogous to antenna arrays imparting directionality to the QCLs, as well as providing means for polarization control. Finally, a research interest in plasmonics led us to design passive flat optical elements using plasmonic antennas. All these projects are tied together by the involvement of Fourier analysis as an essential design tool to predict the interaction of light with various gratings and periodic arrays of grooves and scatterers.Engineering and Applied Sciences
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Letal, Gregory. "Integrated distributed feedback lasers and electroabsorption modulators fabricated using helium-plasma-assisted InP defect induced quantum well intermixing." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0033/NQ66279.pdf.
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Liang, Yong. "Three-dimensional coupled-wave theory for photonic-crystal surface-emitting lasers." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188596.
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Wang, Yue. "Low threshold organic semiconductor lasers and their application as explosive sensors." Thesis, University of St Andrews, 2012. http://hdl.handle.net/10023/3491.
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This thesis presents studies of organic semiconductor lasers, including their operation when pumped by a light-emitting diode (LED), and their application as explosive sensors. The photophysics and amplified spontaneous emission (ASE) of star-shaped oligofluorene truxene molecules were investigated. These materials exhibit high gain and low optical loss in thin-film waveguides. Low ASE thresholds were achieved with the truxene T3 and T4. Second-order distributed feedback (DFB) lasers were fabricated, with pump threshold intensities below 0.5 kW/cm² and broad tunability of the emission. DFB lasers were demonstrated with a novel polymer BBEHP-PPV, pumped by a pulsed commercial InGaN LED. The laser emission occurred at 533 nm for peak drive current above 15 A. The output beams and pulse-dynamics of the lasers were investigated for the first time, along with a 'double-threshold' phenomenon that was observed in this long-pulse pumping regime. BBEHP-PPV lasers based on various types of diffractive resonators were also fabricated by UV nanoimprint-lithography (NIL). By optimising the resonator design and the fabrication, and the pump-beam geometry, polymer laser thresholds of ~60 W/cm², the lowest recorded for NIL lasers, were demonstrated, enabling them to be pumped by pulsed commercial LEDs and custom micro-LED arrays. One promising application of organic lasers is in explosive sensing. A polymer of intrinsic microporosity (PIM-1) was used to detect nitroaromatic vapours. Rapid detection of dinitrobenzene (DNB) of low vapour pressure was achieved by monitoring the photoluminescence and laser emission during exposure. In addition, a CMOS time-resolved fluorescence lifetime microsystem with a commercial green-emitting copolymer was used as a novel, portable sensor to detect DNB vapour. An InGaN LED pumped BBEHP-PPV laser was also used as a miniature sensor to detect 10 ppb of DNB. These highly sensitive hybrid sensors could be used in humanitarian demining, complementing existing technologies leading to improvement in the detection of hazardous objects.
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Yang, Ying. "Organic semiconductor lasers : compact hybrid light sources and development of applications." Thesis, University of St Andrews, 2010. http://hdl.handle.net/10023/2569.
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This thesis describes a number of studies on organic semiconductors as laser gain media with the aim of simplifying the excitation scheme and exploring potential applications. A hybrid device taking the advantage of high power inorganic light emitting diodes (LEDs) and low threshold organic distributed feedback lasers is demonstrated to realize a LED pumped organic laser. When the drive current is higher than 152 A, a sharp peak is clearly observed in the laser output spectrum, implying the LED successfully pumps the polymer laser above threshold. This is the first time an incoherent LED has been used as the excitation source for an organic semiconductor laser. A strategy for further improving the performance of the hybrid device is explored with the use of a luminescent concentrator made of a dye doped SU8 film, to intensify the power density from the inorganic LED. The luminescent concentrator is capable of increasing the incident power density by a factor of 9 and reducing the lasing threshold density by 4.5 times. As a preliminary investigation towards mode-locked polymer lasers, the impact of a solid state saturable absorber on a solution based organic semiconductor laser is explored. The dye doped polystyrene thin film saturable absorber exhibits a saturation intensity of a few MW/cm². When it is placed into the laser cavity, a train of short pulses is generated and the underlying mechanism is discussed. Finally, the potential of using organic semiconductor lasers in the detection of nitro-aromatic explosive vapours is studied in distributed feedback polyfluorene lasers. A high sensing efficiency and fast response from the laser prove polyfluorene lasers can be used as disposal and low cost devices in explosive chemosensing.
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Sindile, Pia. "Probing the dynamic behaviour of ridge waveguide multi-quantum well distributed feedback lasers, fundamental picosecond studies of chirp under large-signal modulation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ63028.pdf.
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Wienold, Martin. "Development of terahertz quantum-cascade lasers as sources for heterodyne receivers." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2012. http://dx.doi.org/10.18452/16560.
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Die vorliegende Arbeit beschäftigt sich mit der Entwicklung und Optimierung von Terahertz-Quantenkaskadenlasern (THz-QCLs) für die Anwendung als Lokaloszillator in THz-Heterodyndetektoren, insbesondere für die Detektion der astronomisch wichtigen Sauerstoff (OI) Linie bei 4.75 THz. Hierfür wurden zunächst unterschiedliche QCL-Heterostrukturen untersucht. Basierend auf einer Heterostruktur, welche schnelle Intersubbandübergänge über Streuung an Phononen ausnutzt, konnten QCLs mit hoher Ausgangsleistung und niedriger Betriebsspannung bei 3 THz erzielt werden. Während diese Laser auf dem Materialsystem GaAs/Al_xGa_(1-x)As mit $x=0.15$ basieren, führt die Erhöhung des Al-Anteils auf x=0.25 für ähnliche Strukturen zu sehr niedrigen Schwellstromdichten. Durch schrittweise Optimierungen gelang es, QCLs zu realisieren, die bei 4.75 THz emittieren. Mit Hilfe von lateralen Gittern erster Ordnung für die verteilte Rückkopplung (DFB) konnten Einzelmoden-Dauerstrichbetrieb mit hoher Ausgangsleistung, sowie Einzelmoden-Betrieb innerhalb des spezifizierten Frequenzbereichs bei 4.75 THz erzielt werden. Eine allgemeine Methode zur Bestimmung der DFB-Kopplungskonstanten erlaubt eine gute Beschreibung der Laser innerhalb der etablierten Theorie der gekoppelten Moden für DFB-Laser mit reflektiven Endfacetten. Oft steht das Auftreten negativer differentieller Leitfähigkeit bei höheren Feldstärken und die damit verbundenen Bildung von elektrischer Felddomänen (EFDs) im Konflikt mit einem stabilen Betrieb der THz-QCLs. Es wird gezeigt, dass stationäre EFDs mit Diskontinuitäten in der statischen Licht-Strom-Spannungskennlinie verbunden sind, während Selbstoszillationen, verursacht durch nicht-stationäre EFDs, eine zeitliche Modulation der Ausgangsleistung bewirken. Mit Hilfe einer effektiven Driftgeschwindigkeit für QCLs lassen sich viele der beobachteten Phänomene durch die nichtlinearen Transportgleichungen für schwach gekoppelte Übergitter beschreiben.This thesis presents the development and optimization of terahertz quantum-cascade lasers (THz QCLs) as sources for heterodyne receivers. A particular focus is on single-mode emitters for the heterodyne detection of the important astronomic oxygen (OI) line at 4.75 THz. Various active-region designs are investigated. High-output-power THz QCLs with low operating voltages and emission around 3 THz are obtained for an active region, which involves phonon-assisted intersubband transitions. While these QCLs are based on a GaAs/Al_xGa_(1-x)As heterostructure with x=0.15, similar heterostructures with x=0.25 allowed for very low threshold current densities. By successive modifications of the active-region design, THz QCLs have been optimized toward the desired frequency at 4.75 THz. To obtain single-mode operation, first-order lateral distributed-feedback (DFB) gratings are investigated. It shows that such gratings allow for single-mode operation in combination with high continuous-wave (cw) output powers. A general method is presented to calculate the coupling coefficients of lateral gratings. In conjunction with this method, the lasers are well described by the coupled-mode theory of DFB lasers with two reflective end facets. Single-mode operation within the specified frequency bands at 4.75 THz is demonstrated. Stable operation of THz QCLs is often in conflict with the occurrence of a negative differential resistance (NDR) regime at elevated field strengths and the formation of electric-field domains (EFDs). Stationary EFDs are shown to be related to discontinuities in the cw light-current-voltage characteristics, while non-stationary EFDs are related to current self-oscillations and cause a temporal modulation of the output power. To model such effects, the nonlinear transport equations of weakly coupled superlattices are adopted for QCLs by introducing an effective drift velocity-field relation.
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Schultz, Christoph Matthias [Verfasser], Günther [Akademischer Betreuer] Tränkle, Götz [Akademischer Betreuer] Erbert, Klaus [Akademischer Betreuer] Petermann, and Hartmut [Akademischer Betreuer] Hillmer. "Analysis and mitigation of the factors limiting the efficiency of high power distributed feedback diode lasers / Christoph Matthias Schultz. Gutachter: Günther Tränkle ; Klaus Petermann ; Hartmut Hillmer. Betreuer: Günther Tränkle ; Götz Erbert." Berlin : Technische Universität Berlin, 2013. http://d-nb.info/106566480X/34.
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Van, Dommelen Ronnie Francis. "Bistable distributed feedback laser diodes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0020/MQ48293.pdf.
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Khairuzzaman, Md. "Digitally selected electronically switchable terahertz-over-fibre." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/digitally-selected-electronically-switchable-terahertzoverfibre(7003c9cb-fa46-4933-9348-b1977a446b7f).html.
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The Quantum Cascade Laser (QCL)-based terahertz-over-fibre (ToF) concept combines the strength of QCLs as ultra-wide bandwidth, high speed data sources, with the mature optical fibre technology. In this thesis, for the first time, by fusing multiple technologies, digitally selected, electronically-switchable ToF concept is experimentally demonstrated. Furthermore, the digital mode selection principle and electronic tuning mechanism provided by novel aperiodic distributed feedback (ADFB) multi-band filters are presented. For the development of electronically tunable ADFB lasers, a range of bound-to-continuum and chirped superlattice terahertz (THz) QCLs are measured across the frequency range 2.9 – 4.5 THz. The availability of these active materials allowed rapid assessments of the optimum design parameters for subsequent measurements. First, a range of photonic lattice-engineered lasers operating at 4.4 THz are characterized and key design parameters identified. Following this initial development, full electrical and spectral characterization of ADFB lasers operating at 2.9 THz are presented. The novelty of this work lies in the first-ever successful demonstration of discretely tunable QCLs, operating at six distinct THz frequencies. The ADFB technology was experimentally applied using various device geometries and gain dynamics. Toward this aim, results are presented for a Y coupled QCL architecture, showing that complex on-chip signal manipulation can be extended into the THz regime. In addition, it is demonstrated that ADFB technology provides broadband multi-channel optical filtering for the entire gain bandwidth. It is shown that discrete, purely electronic, tuning of simultaneous dual colour output can be achieved. Multi band optical filter functions derived from ADFB gratings possess highly nonlinear dispersion across the filter bandwidth and are found to modify the gain-induced, driving current-dependent continuous mode tuning. This thesis, therefore, presents a systematic experimental analysis of the dispersion engineered continuous fine-tuning in THz QCLs. In the final two chapters, the thesis presents, for the first time, transmission of tunable THz signals over standard single-mode optical fibre by up converting 2.9 THz QCL radiation via intra-cavity nonlinear mixing with an optical fibre-injected near-infrared (NIR) carrier in the 1.3 µm band. Discrete and continuous tuning technologies, as developed in chapters 3 – 5, are now successfully transferred to THz sidebands on the NIR carrier, extracted via a butt coupled single mode fibre and recorded using an optical spectrum analyzer. The major novel outcome of this thesis is the first demonstration of electronically tunable phase-matched points in a THz plasmon waveguide. The key breakthrough is the experimental confirmation of the photonic band-gap engineering of group velocity of THz signals – as both ‘fast’ and ‘slow’ switchable side bands are observed. Such novel nonlinear up-conversion of spectrally flexible THz signals may open up new possibilities for ultrafast THz telecom frameworks.
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Todt, René. "Widely tunable laser diodes with distributed feedback /." München : Walter-Schottky-Institut, Technische Universität München, 2006. http://opac.nebis.ch/cgi-bin/showAbstract.pl?u20=3932749790.
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Hadeler, Oliver. "Distributed feedback fibre laser strain and temperature sensors." Thesis, University of Southampton, 2002. https://eprints.soton.ac.uk/46100/.
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This thesis presents the development of two new types of polarimetric distributed feedback (DFB) fibre laser sensors for simultaneous strain and temperature measurements. These fibre Bragg grating (FBG) based sensors offer strain and temperature measurement accuracies of ±0.3 - ±15 με and ±0.04 - ±0.2°C which are suitable for many applications. The main advantage of these DFB fibre laser sensors over other FBG based sensors is the simplicity of their interrogation system. The first type of sensor operates stably in a single longitudinal mode which splits into two orthogonally polarised modes. This sensor utilises the wavelength of one polarisation mode and the RF beat frequency between the two polarisation modes. The system complexity is reduced to a minimum in the dual longitudinal mode polarirnetric DFB fibre laser sensor which utilises the RF beat frequencies between two longitudinal modes and their associated orthogonal polarisations, therefore requiring only a simple and cost effective frequency counter. -ions and pump excited state absorption into account. An extended version of this model incorporates, for the first time, self-heating in DFB fibre lasers which is caused by non-radiative decays. The performance of DFB fibre lasers employed in telecommunication applications is likely to benefit from these modelled results, which are also verified by experimental data.
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Pang, Wing Chung. "Ultrashort pulse generation with a distributed feedback dye laser." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47607.
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Espe, Burt Lann. "MATLAB simulation of a distributed feedback (DFB) laser with chirp effects." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1994. http://handle.dtic.mil/100.2/ADA297053.
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Thesis (M.S. in Electrical Engineering) Naval Postgraduate School, December 1994."December 1994." Thesis advisor(s): John P. Powers,Randy L. Borchardt. Includes bibliographical references. Also available online.
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Kao, Tsung-Yu. "Surface-emitting distributed feedback terahertz quantum-cascade phase-locked laser arrays." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/54235.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 111-114).
A new approach to achieve high-power, symmetric beam-pattern, single-mode THz emission from metal-metal waveguide quantum-cascade laser is proposed and implemented. Several surface-emitting distributed feedback terahertz lasers are coupled through the connection phase sectors between them. Through carefully choosing the length of phase sectors, each laser will be in-phase locked with each other and thus create a tighter beam-pattern along the phased-array direction. A clear proof of phase-locking phenomenon has been observed and the array can be operated in either in-phase or out-of-phase mode at different phase sector length. The phase sector can also be individually biased to provide another frequency tuning mechanism through gain-induced optical index change. A frequency tuning range of 1:5 GHz out of 3:9 THz was measured. Moreover, an electronically controlled "beam steering" device is also proposed based on the result of this work. This thesis focuses on the design, fabrication and measurement of the surface-emitting distributed feedback terahertz quantum-cascade phase-locked laser arrays.
by Tsung-Yu Kao.
S.M.
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Dupont, Tiphaine. "Réalisation de sources laser III-V sur silicium." Phd thesis, Ecole Centrale de Lyon, 2011. http://tel.archives-ouvertes.fr/tel-00604962.
Full textAbstract:
Le substrat SOI (Silicon-On-Insulator) constitue aujourd'hui le support de choix pour la fabrication de fonctions optiques compactes. Cette plateforme commune avec la micro-électronique favorise l'intégration de circuits photoniques avec des circuits CMOS. Néanmoins, si le silicium peut être utilisé de manière très avantageuse pour la fabrication de composants optiques passifs, il présente l'inconvénient d'être un très mauvais émetteur de lumière. Ceci constitue un obstacle majeur au développement de sources d'émission laser, briques de constructions indispensables à la fabrication d'un circuit photonique. La solution exploitée dans le cadre de cette thèse consiste à reporter sur SOI des épitaxies laser III-V par collage direct SiO2-SiO2. L'objectif est de réaliser sur SOI des sources lasers à cavité horizontale permettant d'injecter au moins 1mW de puissance dans un guide d'onde silicium inclus dans le SOI. Notre démarche est de transférer un maximum des fonctions du laser vers le silicium, dont les procédés sont familiers au monde de la micro-électronique. Dans l'idéal, le III-V ne devrait être utilisé que comme matériau à gain ; la cavité laser pouvant être fabriquée dans le silicium. Mais cette ligne de conduite n'est pas forcément aisée à mettre en œuvre. En effet, les photons sont produits dans le III-V mais doivent être injectés dans un guide silicium placé sous l'épitaxie. La difficulté est que les deux matériaux sont séparés par plus d'une centaine de nanomètres d'oxyde de collage faisant obstacle au transfert de photons. Le développement de lasers III-V couplés à un guide d'onde SOI demande alors de nouvelles conceptions du système laser dans son ensemble. Notre travail a donc consisté à concevoir un laser hybride III-IV / silicium se pliant aux contraintes technologiques du collage. En s'appuyant sur la théorie des modes couplés et les concepts des cristaux photoniques, nous avons imaginé, réalisé, puis caractérisé un laser à contre-réaction distribuée hybride (en anglais : " distributed feedback laser ", laser DFB). Son fonctionnement optique original, permet à la fois un maximum de gain et d'efficacité de couplage grâce à une circulation en boucle des photons du guide III-V au guide SOI. Sur ces dispositifs, nous montrons une émission laser monomode (SMSR de 35 dB) à température ambiante en pompage optique et électrique pulsé. Comme attendu, la longueur d'onde d'émission est dépendante du pas de réseau DFB. Les lasers fonctionnent avec une épaisseur de collage de silice de 200 nm, ce qui offre une grande souplesse quant au procédé d'intégration. Tous les lasers fonctionnent jusqu'à des longueurs de 150 μm (la plus petite longueur prévue sur le masque). Malgré les faibles niveaux de puissances récoltés dans la fibre lors des caractérisations, la prise en compte des pertes optiques induites pas les coupleurs fibres nous indique que la puissance réellement injectée dans le guide silicium dépasse le milliwatt. Notre objectif de ce point de vue est donc rempli. Malheureusement le fonctionnement des lasers en injection électrique continue n'a pas pu être obtenu dans les délais impartis. Cependant, les faibles densités de courant de seuil mesurées en injection pulsée (300A / cm2 à température ambiante sur les lasers de 550 μm de long) laissent présager un fonctionnement prochain en courant continu.
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Yeo, Terence E. "Novel high precision microlithographic techniques applicable to distributed feedback laser grating manufacture." Thesis, Loughborough University, 1993. https://dspace.lboro.ac.uk/2134/13625.
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Distributed feedback, DFB, lasers are a major source for long haul optical fibre based telecommunication systems. They rely on ultrahigh precision gratings to reduce mode competition within the laser cavity, thereby making single frequency operation possible. Techniques applied to DFB grating manufacture tend to be either holographic, or a direct serial write process using slow and expensive electron beam lithographic machines. An entirely new approach is proposed which compliments the accuracy of the electron beam systems with the high throughput and relatively low cost of a conventional contact mask regime. The new process relies on a group of materials which are able to retain an embossed relief upon curing with ultraviolet radiation. The main manufacturing stages of this new technique are presented including details of the embossing tool fabrication using reactive ion etching, and characterisation of material properties. It is proposed that the technique, whilst intended for DFB manufacture, could find applications in many other areas, for instance as a route to low cost replication of photomasks. In addition a new grating assessment technique, based on normal reflectance measurements, has been developed. The technique has been used to investigate hitherto unmeasured effects in electron beam lithography on a variety of substrate materials before and after semiconductor overgrowth. Details of a theoretical exercise which agrees closely with experimental results are included. The technique is non-destructive and should be of interest to all areas of microlithography and holographic imaging where it is important to have control over a wide range of process stages or where the feature size rules out the use of conventional optical microscopes.
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Nkanta, Julie Efiok. "Modelling and Characterization of Laterally-Coupled Distributed Feedback Laser and Semiconductor Optical Amplifier." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34869.
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There is an increasing need for tuneable spectrally pure semiconductor laser sources as well as broadband and polarization insensitive semiconductor optical amplifiers based on the InGaASP/InP material system, to be monolithically integrated with other active and passive components in a photonic integrated circuit. This thesis aims to contribute to finding a solution through modelling, experimental characterization and design improvements.
In this thesis we have analyzed laterally-coupled distributed feedback (LC-DFB) lasers. These lasers have the gratings etched directly out of the ridge sidewalls thus lowering the cost associated with the re-growth process required if the gratings were otherwise embedded above the active region. The performance characteristics are analyzed for the LC-DFB lasers partitioned into 1-, 2-, and 3-, electrodes with individual bias control at various operating temperatures. The laser exhibits a stable single mode emission at 1560 nm with a current tuning rate of ~14 pm/mA for a tuning of 2.25 nm. The side modes are highly suppressed with a maximum side-mode suppression ratio of 58 dB. The light-current characteristics show a minimum 40 mA threshold current, and power saturation occurring at higher injection currents. The linewidth characteristics show a minimum Lorentzian linewidth of 210 kHz under free-running and further linewidth reduction under feedback operation. The multi-electrode LC-DFB laser devices under appropriate and selective driving conditions exhibit a flat frequency modulation response from 0 to above 300 MHz. The multi-electrode configuration can thus be further exploited for certain requirements. Simulation results and design improvements are also presented.
The experimental characterization of semiconductor optical amplifier (SOA) and Fabry-Perot (FP) laser operating in the E-band are also presented. For the SOA, the linear vertical and horizontal states of polarization corresponding to the transverse electric (TE) and transverse magnetic (TM) modes were considered. For various input power and bias, performance characteristics shows a peak gain of 21 dBm at 1360 nm, gain bandwidth of 60 nm and polarization sensitivity of under 3 dB obtained for the entire wavelength range analyzed from 1340 to 1440 nm. The analysis presented in this thesis show good results with room for improvement in future designs.
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Gunning, Paul. "Distributed optical TDMA photonic switch fabric based on gain-switched distributed feedback semiconductor laser diodes and electroabsorption modulators." Thesis, University of Essex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247025.
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Al-Hosiny, Najm M. "Nonlinear dynamics of a distributed feedback laser subject to single and dual optical injection." Thesis, University of Essex, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434393.
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SAAVEDRA, ADELA ALENCAR. "STUDY OF FREQUENCY INSTABILITY AND THERMAL EFFECTS IN DISTRIBUTAL FEEDBACK LASERS WITH COHERENT REFLECTOMETRY." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1994. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=8633@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOA reflectometria coerente tem se mostrado uma importante técnica para caracterização dos dispositivos ópticos e optoeletrônicos presentes nos sistemas de comunicações. Neste trabalho, a reflectometria coerente no domínio da freqüência foi utilizada no estudo das características dos lasers de semicondutor de realimentação distribuída. Foram realizadas medidas da resposta térmica do módulo laser, da linearidade da varredura em freqüência e da instabilidade de freqüência devido às reflexões da luz nas conexões do sistema. Conhecendo estas informações é possível saber algumas limitações da técnica. Todas as medidas de caracterização são feitas de formas simples e prática.
Coherente reflectometry has been an important technique for characterization of optinal and optoeletronics devices used in communications systems. In this work, Coherente frequency domain reflectometry was used in the study of the Distributed-Feedback Semiconductor lasers characteristics. The measurement of thermal response of the laser module, linearity of the frequency sweep and frequency instabilities induced by feedback light reflected at the systems conections was was done. With these informations it is possible to know some limitations of the technique.
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Haughey, Anne-Marie. "A distributed feedback for organic semiconductor laser platform for assessing the risk of cardiovascular disease." Thesis, University of Strathclyde, 2014. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=24548.
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Organic distributed feedback (DFB) lasers are a class of evanescent wave technology that can be used to measure changes in refractive index at the laser surface. These sensors are highly attractive for biosensing applications as they provide a sensitive platform for the label-free detection of a range of analytes, possibly in real-time, and they can be multiplexed for the detection of a suite of different analytes from a single test sample. The simple implementation of DFB lasers for sensing also means that they can be packaged into a compact sensing platform; this is especially true of DFB lasers incorporating an organic semiconductor as the gain layer where optical pumping may be performed with a compact source, such as a laser diode. In addition, organic semiconductor based DFB lasers have the potential for improved sensitivity relative to other organic DFB lasers (such as dye-doped) as the refractive index of organic semiconductors is generally higher, which leads to an increase in the interaction of the laser mode with the analyte binding region at the laser surface. In this thesis, the rst demonstration of an organic semiconductor (oligofluorene truxene (T3)) DFB laser for biosensing applications is described. Sensor development is focused on the ultimate aim of incorporating a T3 DFB laser into a compact and portable highthroughput sensing platform for the detection of cardiac biomarkers, Apolipoprotein B100, C-reactive protein and B-type natriuretic peptide in particular. Detection of these biomarkers is to be achieved via functionalisation of the T3 surface with oligonucleotide based probes. The structure of the T3 DFB laser is optimised experimentally and theoretically by tuning the gain layer thickness to maximise sensitivity to changes in refractive index at the laser surface, such as the binding of an analyte. The optimised laser sensor has a laser threshold of 30 µJ.cm⁻²/6 kW.cm⁻² (5 ns pulse duration) which makes optical pumping with a laser diode a possibility. The sensing potential of the DFB laser is shown via the detection of bulk solution refractive index changes and the addition of biomolecules to the laser surface, where a bulk sensitivity of 22 nm per refractive index unit is observed. The specific biosensing potential of the laser is highlighted through the functionalisation of the laser surface with biotin molecules and the subsequent detection of the complementary protein, avidin. The lowest limit of avidin detection achieved is 1µg.mL⁻¹; at this level of sensitivity, the current T3 laser is expected to be able to detect the larger and more abundant of two of the three cardiac biomarker targets, ApoB and CRP. The effects of structural changes to device sensitivity are modelled theoretically and demonstrate that detection of BNP may be achieved through the addition of a high-index cladding layer, a technique currently used for dye-doped DFB lasers. The first demonstration of a DFB laser used for reversible sensing is also presented in this thesis. Through the use of desthiobiotin, a biotin analogue, reversible avidin detection is performed. A reversible biosensor may be of particular interest for applications where a large number of repeated measurements are required, and may be prohibitive to the use of single-use, disposable sensors. Finally, functionalisation of the DFB laser with oligonucleotide probes is described. Several different techniques are explored for immobilisation of oligonucleotide probes on the T3 surface, with click chemistry and sulfhydryl linkage chemistries showing the most promise.
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Yu, Zhou. "Optical Properties of Deoxyribonucleic Acid (DNA) and Its Application in Distributed Feedback (DFB) Laser Device Fabrication." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1154706431.
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Isenor, Glenn David. "A novel approach to the reduction of a distributed feedback laser's intensity profile non-uniformity using global optimization." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ63477.pdf.
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Kechaou, Khalil. "Modélisation et caractérisation de sources optiques pour les réseaux d'accès et métropolitains." Phd thesis, Télécom ParisTech, 2012. http://pastel.archives-ouvertes.fr/pastel-00998832.
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Le déploiement des réseaux optiques d'accés et métropolitains à crée un besoin incessant de débits élevés et de portées étendues. Une demande pour des sources optiques compactes, polyvalentes, de bas coût et de consommation réduite a vu le jour dans ce contexte. Le but de cette thèse consiste à étudier expérimentalement et par la simulation deux techniques pour combattre les effets de la dispersion chromatique à travers l'ingénierie du chirp de la source. La première technique concerne les lasers DFB (Distributed Feedback Laser) modulés directement. Premièrement, un modèle complet et flexible d'un laser DFB développé au cours de la thèse a été exploité pour confirmer l'étude expérimentale des effets de phases du réseau de Bragg aux facettes sur le comportement du chirp. Les résultats ont montré l'existence de deux familles de lasers définies suivant la position du mode d'émission par rapport à la bande interdite. Deuxiémement, une étude théorique et expérimentale a montré la stabilisation et le contrôle du chirp des lasers DFB via la présence d'une rétroaction optique externe bien ajustée. La deuxième technique concerne le concept de la modulation duale des lasers modulateurs intégrés (D-EML : Dual Electroabsorption Modulated Laser) exploitant l'ajustement de la dérive en fréquence résultant de la juxtaposition d'une modulation de fréquence appliquée sur le laser et une modulation d'intensité appliquée sur le modulateur. L'évaluation expérimentale et théorique des performances du D-EML a permis de prouver sa compatibilité aux hauts débits (20, 25 et 40 Gb/s) ainsi que son efficacité par rapport à la modulation simple de l'EAM (Electro-Absorption Modulator).
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Moore, Jeanne. "TRANSPORTATION OF THE RF SPECTRA OVER FIBER: A WORKING SYSTEM." International Foundation for Telemetering, 2000. http://hdl.handle.net/10150/606790.
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International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, CaliforniaThis paper presents the results of installing a distributed feedback (DFB) laser transmitter and the appropriate optical receiver in an operational site. Frequencies from 1435 to 2400 megahertz are transported intact from a remote site to a local site. From the theoretical calculations, 10 dB of dynamic range may need to be recovered by the use of an automatic gain circuit. The actual device is a delight, needing no additional circuitry to meet specifications. Predictions of performance were made from calculations. The installed system was measured for 1 dB compression point and for figure of merit.
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"Distributed feedback dye-doped sol-gel silica lasers." 2001. http://library.cuhk.edu.hk/record=b6073321.
Full textAbstract:
Zhu Xiao Lei.Thesis (Ph.D.)--Chinese University of Hong Kong, 2001.
Includes bibliographical references (p. 116-121).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Mode of access: World Wide Web.
Abstracts in English and Chinese.
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"Distributed feedback sol-gel channel waveguide lasers." 2005. http://library.cuhk.edu.hk/record=b5892398.
Full textAbstract:
Chen Fei.Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.
Includes bibliographical references (leaves 86-92).
Abstracts in English and Chinese.
Acknowledgements --- p.i
List of publications --- p.ii
Abstract (In English) --- p.iii
Abstract (In Chinese) --- p.v
Table of contents --- p.vii
List of figures --- p.x
List of tables --- p.xiv
Chapter Chapter I --- Introduction --- p.1
Chapter Chapter II --- Sol-gel channel waveguides --- p.6
Chapter 2.1 --- General sol-gel process --- p.6
Chapter 2.2 --- Dye-doped sol-gel zirconia and zirconia-ORMOSIL materials --- p.10
Chapter 2.3 --- Fabrication of sol-gel channel waveguides --- p.15
Chapter 2.3.1 --- General process of the photolithographic technique --- p.15
Chapter 2.3.2 --- Channels in glass substrates by using photolithographic wet etching technique --- p.19
Chapter 2.3.3 --- Channels in fused silica substrates by using photolithographic dry etching technique (Inductive-coupled plasma etching) --- p.24
Chapter Chapter III --- Coupled-wave theory and experimental setup of distributed feedback channel waveguide lasers --- p.27
Chapter 3.1 --- Coupled-wave theory of distributed feedback lasers --- p.27
Chapter 3.2 --- Experimental setup --- p.33
Chapter Chapter IV --- One-dimensional and two-dimensional optical waveguide analysis --- p.37
Chapter 4.1 --- 1-D planar waveguide analysis --- p.37
Chapter 4.2 --- 2-D channel waveguide analysis using the Marcatili method --- p.39
Chapter 4.2.1 --- The Eypq modes: Polarization in the y direction --- p.42
Chapter 4.2.2 --- The Eypq modes: Polarization in the x direction --- p.46
Chapter 4.3 --- 2-D channel waveguide analysis using the effective index method --- p.48
Chapter Chapter V --- Distributed feedback channel waveguide lasers tunable in the visible --- p.50
Chapter 5.1 --- Rhodamine 6G-doped zirconia planar and channel waveguides --- p.51
Chapter 5.2 --- Results and discussion --- p.56
Chapter 5.3 --- Summary --- p.66
Chapter Chapter VI --- Near infrared distributed feedback channel waveguide lasers --- p.68
Chapter 6.1 --- LDS dye-doped zirconia-ORMOSIL planar and channel waveguides --- p.68
Chapter 6.2 --- Results and discussion --- p.72
Chapter 6.3 --- Summary --- p.80
Chapter Chapter VII --- Summary --- p.81
References --- p.86
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"Distributed feedback zirconia and zirconia-ORMOSIL waveguide lasers." 2003. http://library.cuhk.edu.hk/record=b5891528.
Full textAbstract:
Wang Jun.Thesis (M.Phil.)--Chinese University of Hong Kong, 2003.
Includes bibliographical references (leaves 74-79).
Abstracts in English and Chinese.
Acknowledgements --- p.i
List of publications --- p.ii
Abstract (In English) --- p.iii
Abstract (In Chinese) --- p.v
Table of contents --- p.vii
List of figures --- p.x
List of tables --- p.xiv
Chapter Chapter I --- Introduction --- p.1
Chapter Chapter II --- Dye-doped sol-gel zirconia and zirconia-organically modified silicate waveguides --- p.6
Chapter 2.1 --- General sol-gel process --- p.6
Chapter 2.2 --- Dye-doped sol-gel zirconia and zirconia-ORMOSIL waveguides --- p.7
Chapter Chapter III --- Basic theory and experiment setup of distributed feedback waveguide lasers --- p.13
Chapter 3.1 --- Coupled-wave theory of distributed feedback lasers --- p.13
Chapter 3.2 --- Introduction on the theory of planar optical waveguide --- p.16
Chapter 3.3 --- Experiment setup design of DFB waveguide lasers --- p.19
Chapter Chapter IV --- Zirconia and zirconia-organically modified silicate distributed feedback waveguide lasers tunable in the visible --- p.23
Chapter Chapter V --- Tunable multi-wavelength distributed feedback zirconia waveguide lasers --- p.35
Chapter 5.1 --- Brief introduction on multi-wavelength lasers --- p.35
Chapter 5.2 --- R6G-doped zirconia multi-mode waveguides --- p.36
Chapter 5.3 --- Experimental results and discussion --- p.39
Chapter 5.3.1. --- Dual- and quadruple-wavelength DFB waveguide lasers --- p.39
Chapter 5.3.2. --- The dispersion characteristics of multi-wavelength DFB waveguide lasers --- p.44
Chapter 5.3.3. --- Determination of waveguide parameters by the DFB technique --- p.48
Chapter 5.4 --- Summary --- p.51
Chapter Chapter VI --- Distributed feedback laser action in sol-gel glass symmetric waveguides --- p.53
Chapter 6.1 --- The fabrication of dye-doped glass symmetric waveguides --- p.54
Chapter 6.2 --- Experimental results and discussion --- p.56
Chapter 6.2.1. --- DFB laser action in sol-gel glass symmetric-asymmetric waveguide --- p.56
Chapter 6.2.2. --- Dispersion characteristics of DFB symmetric and asymmetric waveguide lasers --- p.61
Chapter 6.3 --- Summary --- p.65
Chapter Chapter VII --- Summary --- p.69
References --- p.74
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Cheng, Hsing-Chieh, and 鄭行傑. "Fabrication and Applications of Organic Distributed Feedback Lasers." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/19422738689575142647.
Full textAbstract:
博士國立臺灣大學
光電工程學研究所
101
Distributed feedback organic lasers have been the subjects of intense investigation recently due to their applications in organic sensors, optical communications, spectroscopy, integrated optical devices, and biological areas. In this thesis, we investigate the process and the characteristics of organic distributed feedback lasers and discuss possible applications. We first employed electron beam lithography (EBL) and reactive ion etching (RIE) to realize the high-quality distributed feedback (DFB) resonant/cavity. The T3 organic laser utilizing this distributed feedback resonant/cavity exhibited low lasing threshold. The characteristics of lasing can be tuned by variations of distributed feedback parameters. Based on the earlier results of the molecular reoriention in T3 thin films by annealing, the effective refractive index of T3 distributed feedback laser can be tuned after T3 deposition by annealing. Employing such properties, we have also demonstrated continuous tuning of the lasing wavelength of a T3 distributed feedback laser within one sample. Besides, we also studied another approach to realize emission wavelength tuning of a distributed feedback organic laser within one sample by utilizing stretchable/elastic substrates. Employing such stretchable/elastic substrates, we have also demonstrated continuous tuning of the lasing wavelength of an organic distributed feedback laser within one sample. Finally, we employed the oligofluorene thin film to realize the distributed feedback organic laser for oxygen sensing. The material itself exhibits moderate sensitivity and fast response in this application. The sensitivity can be further enhanced using the T3 DFB laser structure.
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Li, Jingsi. "Distributed feedback lasers and integrated laser arrays for wavelength-division multiplexing systems." Thesis, 2014. http://hdl.handle.net/2152/30490.
Full textAbstract:
Distributed Feedback (DFB) lasers and integrated laser arrays are of great importance in Wavelength-Division Multiplexing (WDM) systems in fiber optic communication systems. High-performance, low-cost DFB lasers and laser arrays are highly desirable for applications in intra-datacenter transport and in local access networks. This dissertation is focused on the design, fabrication and achievement of high-performance, low-cost DFB Lasers and Integrated DFB Arrays for WDM Systems. It investigates the use of a novel sampled grating approach, called the equivalent phase shift method, to achieve integrated DFB laser arrays with single-mode lasing at uniformly-spaced and precisely-positioned wavelengths. First, laterally-Coupled DFB (LC-DFB) lasers with first-order sidewall gratings are realized, with gratings fabricated by optical interference lithography instead of e-beam. Then, LC-DFB lasers and LC-DFB laser arrays with sampled gratings and equivalent phase shifts are proposed, numerically analyzed and experimentally demonstrated. Each LC-DFB laser with an equivalent quarter-wave phase shift is shown to lase at the pre-specified wavelength in a single longitudinal mode, with good side-mode suppression ratio (SMSR) over a very wide range of injection currents. Integrated LC-DFB laser arrays with five uniformly-spaced wavelength channels are demonstrated, in close agreement with the design. For better performance, buried heterostructure (BH)-DFB laser and laser arrays are also demonstrated using the same sampled-grating technology. A 6-wavelenth laser array with a 300 μm cavity length and a 8-wavelength laser array with 250 μm cavity length are successively demonstrated, each showing precisely positioned lasing wavelengths, good SMSR, and uniformly good lasing characteristics under a wide range of operating currents and temperatures. Finally, it is demonstrated that the wavelength of a monolithic WDM laser array can be continuously tuned over a very wide wavelength range of nearly 40 nm. The proposed method offers a practical and cost-effective solution for the manufacture of high-performance, monolithic multi-wavelength DFB laser arrays as well as widely wavelength-tunable DFB lasers for integrated WDM systems.
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"Experimental and theoretical studies of distributed feedback waveguide lasers." Thesis, 2006. http://library.cuhk.edu.hk/record=b6074265.
Full textAbstract:
As an effective compact coherent light source, distributed feedback (DFB) waveguide laser has attracted much attention recently. Sol-gel Mass synthesized at low temperatures is a very useful optical material. DFB waveguide lasers based on sol-gel glasses were experimentally and theoretically investigated in this thesis. In addition, microring lasers based on a conjugated polymer, which is emerging as an important class of laser material, were also studied in this thesis.DFB lasing characteristics of various dyes in zirconia waveguides and in solutions were investigated. Intensity modulation and polarization modulation were used to generate the laser action. The laser output showed different polarization characteristics and threshold energy variation when the feedback mechanism was changed from intensity modulation to polarization modulation. In addition, near infrared (NIR) wide-band tuning DFB lasing operation was achieved in NIR dve-doped sol-gel waveguides by using intensity modulation.
Microring cavities were fabricated by depositing poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene) (MEH-PPV) on glass fibers by a dip coating method. Laser emissions in whispering gallery modes using microring cavities were observed by pumping with a frequency-doubled Nd:YAG laser. The threshold energy of the MEH-PPV microring laser was as low as 10 nJ per pulse. The polarization characteristics of the microring lasers were studied and a polarization model was developed to explain the observed phenomena.
Theoretical expressions for the angle-dependent coupling coefficients of DFB lasers were derived to explain the polarization properties of the DFB lasers. The coupling and gain coefficients of the two orthogonal polarization components of DFB lasers are strongly dependent on the intersection angle and the polarization states of the two crossing pump heams. The experimental results of DFB lasing in dye solutions have verified our theoretical predictions.
Titania zirconia organically modified silicate (TiO2-ZrO 2-ORMOSIL) DFB waveguide lasers were demonstrated. The output polarization and output wavelength of TiO2-ZrO2-ORMOSIL DFB waveguide lasers were found to be dependent on the polarization of the crossing pump beams from a frequency-doubled Nd:YAG laser. Up to sixteen Output wavelengths corresponding to eight pairs of polarized output from eight propagation modes were observed simultaneously for a planar waveguide with a thickness of 6.7 mum.
Two-photon-pumped DFB lasing action with a narrow linewidth output was demonstrated in zirconia waveguides doped with trans-4-[p-( N-hydroxyethyl-N-methylamino)styryl]-N-methylpyridinium p-toluene sulfonate a compound that shows strong two-photon upconverted emission around 620 nm. Transient gratings for coherent scattering were generated in the waveguides by crossing two 1.06 mum beams. DFB laser emission with the linewidth as narrow as 60 pm was observed. Operating at the third-order Bragg condition, tunable TE mode laser emission was achieved from 618 to 640 nm. TM output modes from the DFB laser were observed when the crossing beams were changed from s-polarized to p-polarized.
Wang Jun = 分佈反饋波導激光器的實驗與理論研究 / 王俊.
"September 2006."
Adviser: King Young Wong.
Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1702.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2006.
Includes bibliographical references (p. 165-183).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstracts in English and Chinese.
School code: 1307.
Wang Jun = Fen bu fan kui bo dao ji guang qi de shi yan yu li lun yan jiu / Wang Jun.
50
"Computer modeling and analyses of multisection distributed feedback lasers." Chinese University of Hong Kong, 1995. http://library.cuhk.edu.hk/record=b5895469.
Full textAbstract:
by So-kuen C. Liew.Thesis (Ph.D.)--Chinese University of Hong Kong, 1995.
Includes bibliographical references (leaves [40-45, 3rd gp.]) and index.
Abstract --- p.ii
Acknowledgments --- p.iv
Table of Contents --- p.v
Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- Distributed Feedback Lasers --- p.1
Chapter 1.2 --- Computer Model --- p.6
Chapter 1.3 --- Analyses --- p.8
Chapter 1.4 --- Organization of Thesis --- p.11
Chapter 2 --- Computer Model --- p.13
Chapter 2.1 --- Comparison of Theoretical Models --- p.15
Chapter 2.2 --- Assumptions and Approximations --- p.17
Chapter 2.2.1 --- Longitudinal Spatial Hole Burning --- p.17
Chapter 2.2.2 --- Spontaneous Emission --- p.18
Chapter 2.2.3 --- Nonlinear Gain Saturation --- p.19
Chapter 2.2.4 --- Carrier-Induced Index Change --- p.20
Chapter 2.2.5 --- Single-mode Operation Assumption --- p.22
Chapter 2.2.6 --- Otbers --- p.22
Chapter 2.3 --- Theories and Approaches --- p.25
Chapter 2.3.1 --- Coupled Wave Theory --- p.25
Description --- p.25
Stop-Band --- p.29
Second-Order DFB Laser --- p.30
DFB Designs To Improve SMSR --- p.30
Chapter 2.3.2 --- Transfer Matrix Approach --- p.32
Chapter 2.4 --- Above-Threshold Model --- p.34
Chapter 2.4.1 --- Introduction --- p.34
Chapter 2.4.2 --- Formalism --- p.36
Facet Output Power and Optical Spectrum --- p.39
Photon Density Distribution --- p.41
Variance of Photon Density Distribution --- p.42
Nearfield Distribution --- p.42
Surface Emission --- p.43
Power-Current Characteristics --- p.44
Optical spectrum --- p.45
Subthreshold Analysis --- p.47
Linear Yield Analysis --- p.47
Chapter 2.4.3 --- Computer Implementation --- p.48
Flowchart --- p.48
Subroutines --- p.52
"Runtime, Numerical Stability" --- p.56
Chapter 2.5 --- "Discussion,Summary and Future Work" --- p.59
Chapter 2.5.1 --- Validation of the DFB Model --- p.59
Chapter 2.5.2 --- Summary --- p.67
Chapter 2.5.3 --- Topics for Future Work in Theoretical Modeling --- p.68
Chapter 3 --- Analysis of DFBDBR Laser --- p.72
Chapter 3.1 --- Introduction --- p.72
Chapter 3.2 --- Subthreshold Analysis --- p.78
Chapter 3.2.1 --- Introduction --- p.78
Chapter 3.2.2 --- Results --- p.81
Symmetric End-Sections --- p.81
Asymmetric End-Sections --- p.85
Chapter 3.3 --- Above-threshold Analysis --- p.88
Chapter 3.3.1 --- Analysis --- p.89
Chapter 3.3.2 --- Length Ratio --- p.92
Chapter 3.3.3 --- Design Plot --- p.99
Chapter 3.3.4 --- Longitudinal Spatial Hole Burning --- p.102
Chapter 3.3.5 --- Effective Linewidth Enhancement Factor --- p.104
Chapter 3.3.6 --- Asymmetric DFBDBR --- p.107
Chapter 3.4 --- Conclusion --- p.109
Chapter 4 --- Analysis of Complex-Coupled DFB --- p.110
Chapter 4.1 --- Introduction --- p.110
Chapter 4.2 --- Laser Structure --- p.113
Chapter 4.2.1 --- Grating Layer --- p.114
Chapter 4.2.2 --- Parameter Values --- p.119
Chapter 4.3 --- Above-Threshold Analysis of CCDFB --- p.122
Chapter 4.3.1 --- Threshold Current --- p.122
Grating Duty Cycle = 0.36 --- p.122
Grating Duty Cycle = 0.15 --- p.128
Chapter 4.3.2 --- Power Efficiency --- p.131
Grating Duty Cycle = 0.36 --- p.131
Grating Duty Cycle = 0.15 --- p.136
Chapter 4.3.3 --- Summary --- p.137
Chapter 4.4 --- Yield Analysis of LCDFB and QWDFB --- p.138
Chapter 4.4.1 --- Introduction --- p.138
Chapter 4.4.2 --- Method --- p.140
Chapter 4.4.3 --- Results --- p.141
Facet Phase Angle --- p.141
Quarterwave Phase-Shifted DFB Laser --- p.144
Loss-Coupled DFB Laser --- p.148
Chapter 4.5 --- Conclusion --- p.154
Chapter 5 --- Summary and Conclusion --- p.157
Chapter 5.1 --- Summary --- p.157
Chapter 5.1.1 --- Summary of Major Contributions --- p.157
Chapter 5.1.2 --- Summary of Modeling and Validation --- p.159
Chapter 5.1.3 --- Summary of Model Applications --- p.160
DFBDBR Laser --- p.161
Loss-Coupled DFB Laser --- p.162
Chapter 5.2 --- Topics for Future Studies --- p.163
References --- p.R-l
Appendices --- p.A-l
Chapter A. --- Derivations --- p.A-l
Chapter A.1 --- Noise Power --- p.A-l
Chapter A.2 --- Product of Field Vector and Its Adjoint --- p.A-2
Chapter A.3 --- Gain-Coupling Coefficient --- p.A-5
Chapter B. --- Subroutines in Computer Program --- p.A-8
Chapter B.l --- Subroutines in 'drive.f' --- p.A-8
Chapter B.2 --- Subroutines in 'Core.f' --- p.A-9
Chapter B.3 --- Subroutines in 'initiaLf' --- p.A-13
Chapter B.4 --- Subroutines in ´بmisc.f' --- p.A-14
Chapter C. --- List of Figures --- p.A-17
Chapter D. --- List of Tables --- p.A-22
Chapter E. --- List of Abbreviations and Acronyms --- p.A-23
Chapter F. --- List of Symbols --- p.A-24
Chapter G. --- List of Publications --- p.A-27
Index --- p.I-1