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Dissertations / Theses on the topic 'Optical Modulation'
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Haris, Muhammad. "Advanced modulation formats for high-bit-rate optical networks." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24811.
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Thesis (Ph.D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008.Committee Chair: Chang, Gee-Kung; Committee Co-Chair: Yu, Jianjun; Committee Member: Altunbasak, Yucel; Committee Member: Ji, Chunayi; Committee Member: Ralph, Stephen; Committee Member: Xu, Jun.
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Tsai, Hsin-Yu Sidney. "Absorbance modulation optical lithography." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/42253.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 91-94).
In this thesis, the concept of absorbance-modulation optical lithography (AMOL) is described, and the feasibility experimentally verified. AMOL is an implementation of nodal lithography, which is not bounded by the diffraction limit of incident lights. Experimental results showed promising capability of AMOL and matched well with simulation. Several key elements of the AMOL system are discussed: the material systems of AMOL, limitations on the material and optical systems presented, and the design and fabrication of spiral phase elements that generate ring-shaped beams required by AMOL.
by Hsin-Yu Sidney Tsai.
S.M.
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Hong, Stanley Seokjong 1977. "Surface acoustic wave optical modulation." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/86715.
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Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.Includes bibliographical references (leaves 50-54).
by Stanley Seokjong Hong.
M.Eng.
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Joshi, Harita. "Modulation for optical wireless communications." Thesis, University of Warwick, 2012. http://wrap.warwick.ac.uk/55521/.
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davoudzadeh, mahboub sedigh Nima. "optical engineer." OpenSIUC, 2014. https://opensiuc.lib.siu.edu/dissertations/894.
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In this research an approach to all optical delta sigma modulator (ADSM) has been elaborated. Two important components of ADSM; "leaky integrator" and "inverted bi-stable quantizer" were modeled, on the basis of cross gain modulation of the Semiconductor Optical Amplifier (SOA). The simulations (via VPI photonics) were all in micrometer scale (suitable for chip fabrication). By simulating each element of ADSM the whole circuit was simulated and results have been showed and analyzed. By investigating the ADSM, the limiting factor for reaching higher frequencies (THz) was recognized to be the quantization device. Thus a new optical switch was introduced, for the first time so called "proteresis." By applying proteretic bi-stable device in the delta sigma modulator, the resonance frequency was improved minimum two fold from 295MHz to 575MHz without making any change in hysteretic bi-stable switch. The broad impact of this research is on the digital technologies that can be utilized in high-speed signal processing. The prime examples are the RF technologies used in military and civilian applications. Furthermore introduction of proteresis opens a new research gate for compensating delay in almost every system.
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Bhatranand, Apichai. "Electrooptic light modulator with improved response linearity using optical feedback." Diss., Texas A&M University, 2004. http://hdl.handle.net/1969.1/2750.
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The use of optical feedback for improving response linearity of electrooptic light modulators has been investigated. The modulator is configured as a straight channel waveguide flanked by electrodes in a lithium niobate (LiNbO3) substrate. Light is coupled into the waveguide in both TE and TM polarizations, and a voltage applied across electrodes causes a relative phase shift between two polarization components. An output analyzer converts the phase modulation to intensity modulation. Optical feedback of light in both polarization modes results from reflection of light at the polished edges of the substrate. Channel waveguides supporting a single guided mode for TE and TM polarizations were fabricated in x-cut LiNbO3 substrates using titanium-indiffusion technique. The waveguides and modulators were characterized at a wavelength of 1.55 ??m using a distributed feedback laser. The modulators were driven with a sinusoidal voltage waveform. To minimize harmonics of the modulating frequency in the intensity output, the magnitude of the optical feedback and the substrate temperature were adjusted. The feedback level was altered by applying refractive index-matching liquid to one or both ends of the waveguide at the edges of the crystal. It was found that a high degree of response linearity in the presence of feedback was achievable at certain substrate temperatures. The spurious-free dynamic range (SFDR) relative to the noise floor was measured at different feedback levels and substrate temperatures in an effort to maximize the modulator response linearity. An SFDR of 68.04 dB, limited by third-order nonlinearity, was achieved by applying index-matching fluid to the input end of the substrate. This compares with an SFDR of 64.84 dB limited by second-order nonlinearity when index-matching fluid was applied at both ends of the substrate. By changing the temperature of the same substrate to adjust the phase shifts experienced by TE and TM polarizations, the SFDR with index-matching fluid at the input end increased to 71.83 dB, limited by third-order nonlinearity. In tests at constant modulation depth, an improvement of as much as 9.6 dB in SFDR vs. the theoretical value for an interferometric modulator without feedback was achieved.
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Wang, Jun. "All-optical microwave filters based on optical phase modulation." Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/27192.
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In this thesis three different microwave filter architectures based on optical phase modulation are proposed and demonstrated.
The first photonic microwave filter consists of an electro-optic phase modulator (EOPM), a length of high birefringence (Hi-Bi) fiber, a 25-km single-mode fiber and a narrow linewidth laser source.
In the second and the third photonic microwave filters, we focus on the technique to obtain bipolar coefficients based on phase modulation to intensity modulation (PM-IM) conversion. In the second filter, chirped fiber Bragg gratings (CFBGs) are used as PM-IM conversion devices.
In the third filter, the negative coefficients are obtained by locating the optical carriers at the opposite slopes of the transfer function of an optical filter, to convert the phase-modulated signals to intensity-modulated signals, with phase inversion of the RF modulating signals. Based on this scheme, a two-tap microwave bandpass filter with one negative coefficient is demonstrated. (Abstract shortened by UMI.)
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Ferreira, Ricardo Xavier da Graça. "Acoustic optical modulation in optical fibre for sensing applications." Master's thesis, Universidade de Aveiro, 2013. http://hdl.handle.net/10773/11646.
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Mestrado em Engenharia FísicaO presente trabalho teve como objetivo desenvolver um sensor de fibra óptica intrínseco para viscosidade com base no efeito acústoótico aplicado em redes de Bragg. Foram utilizadas fibras de silica e poliméricas para medições com baseadas no espectro e no tempo de resposta da rede quanto sujeitas ao efeito acústo-ótico. O resultado é um viscosímetro multi-paramétrico com um distinto potencial futuro. Com base no conhecimento adquirido, é proposto um novo design e mecanismo de detecção.
The present work aimed to develop an intrinsic optical fibre sensor for viscosity based on the acousto-optic effect applied into fibre Bragg grating. Polymer and silica optical fibres were employed for measurements based on the spectra and the grating response times when subjected to the acousto-optic effect. The results is a multi-parameter viscometer with a distinctive future potential. Based on the knowledge acquired, a new design and sensing mechanism is advanced.
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Robinson, Risa J. "Polarization modulation and splicing techniques for stressed birefringent fiber /." Online version of thesis, 1995. http://hdl.handle.net/1850/12228.
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Yekani, Khoei Aminreza. "Advanced modulation for optical communication systems." Doctoral thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/33709.
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La demande toujours croissante pour la capacité du réseau conduit au développement de systèmes de communication optique pour couvrir les normes Terabit Ethernet récemment proposées. Les applications de courte distance nécessitent une solution peu coûteuse et peu complexe avec détection directe. Cependant, le coût de la détection cohérente diminue chaque jour et en fait un bon candidat pour les applications à courte distance futures afin d'accroître l'efficacité spectrale et d'utiliser des formats de modulation avancés. Dans cette thèse, nous étudions des solutions pour les applications court-courrier actuelles et futures. Dans la première partie, nous nous concentrons sur des solutions pour les applications de courte distance. Le premier chapitre est la première démonstration de la transmission multi-tonalité discrète (DMT) à plus de 100 Gb/s en utilisant une photonique au silicium en bande O (SiP). Nous comparons expérimentalement le DMT avec la modulation d'amplitude d'impulsion (PAM) sur la bande O. Notre expérience montre qu'en augmentant la longueur des fibres de plus de 10 km, la PAM surpasse le DMT. Pour la bande C, nous utilisons un multi-ton discret à bande latérale unique (SSB-DMT) pour éviter l'effet d'évanouissement de la puissance induit par la dispersion chromatique. Nous étudions l'effet du bruit de phase, de la dispersion chromatique et de la sensibilité du récepteur pour optimiser le signal du DMT et extraire des équations théoriques pour calculer le taux d'erreur binaire (BER) du SSB-DMT. Ensuite, nous comparons la PAM sur bande O avec le SSB-DMT sur bande C et quantifions l'impact des limitations imposées par le matériel sur les deux formats de modulation. Notre étude fournit un outil analytique pour les applications de courte distance afin de sélectionner le format et le matériel de modulation appropriés en fonction de la portée requise, du débit binaire, etc. Dans la deuxième partie, le ciblage des futurs systèmes de détection cohérents justifié l'utilisation d'un format de modulation complexe avec détection cohérente. Nous utilisons un format de modulation avancé dans lequel nous avons combiné la propagation de transformée de Fourier discrète avec le DMT pour augmenter l'efficacité spectrale. Le format de modulation hybride a un rapport de puissance crête à moyenne inférieur (vis-à-vis du DMT) et une efficacité spectrale plus élevée (vis-à-vis de la QAM _a porteuse unique). Dans la première étape, nous comparons expérimentalement les performances des modulations hybrides, DMT standard et monoporteuse en utilisant un modulateur SiP IQ. Ensuite, nous développons une stratégie de contrôle pour le format de modulation hybride en échangeant la non-linéarité de la fonction de transfert du modulateur et le rapport signal / bruit optique. Le format de modulation hybride est ensuite optimisé pour avoir un débit maximum. En utilisant une simulation de Monte Carlo, nous comparons le format de modulation hybride optimisé avec le DMT standard pour différents débits binaires. Enfin, nous avons une comparaison de complexité entre hybride et DMT pour différentes longueurs de fibre.Ever increasing demand for network capacity is driving the development of optical communication systems to cover recently proposed Terabit Ethernet standards. Short haul applications need low cost and low complexity solutions with direct detection, as the cost of coherent detection comes down, it will become a good candidate for future short-haul applications to increase spectral efficiency and exploit advanced modulation formats. In this thesis, we investigate solutions for both current and future short-haul systems. In the first part, we focus on solutions for short haul applications. The first chapter is the first time demonstration of more than 100 Gb/s discrete multi-tone (DMT) transmission using an O-band silicon photonics (SiP). We experimentally compare DMT with pulse amplitude modulation (PAM) on O-band. Our experiment shows that by increasing fiber length more than 10 km, PAM outperforms DMT. For C-band, we use single sideband discrete multi-tone (SSB-DMT) to avoid chromatic dispersion-induced power fading e_ect. We study the effect of phase noise, chromatic dispersion, and receiver sensitivity to optimize DMT signal and extract theoretical equations to calculate bit error rate (BER) of SSB-DMT. Next, we analytically compare PAM on O-band with SSB-DMT on C-band and quantify the impact of hardware-imposed limitations on both modulation formats. Our study provides an analytical tool for short haul applications to select appropriate modulation format and hardware based on required reach, bit rate, etc. In the second part we examine complex modulation formats that will be enabled in the future by low cost, integrated components for coherent detection.. We use an advanced modulation format in which we combined discrete Fourier transform spread with DMT to increase spectral efficiency. Hybrid modulation format has a lower peak to average power ratio (vis-a-vis DMT) and higher spectral efficiency (vis-a-vis single carrier QAM). In the first step, we experimentally compare the performance of the hybrid, standard DMT, and single carrier modulations using a SiP IQ modulator. Next, we develop a driving strategy for hybrid modulation format by trading off the modulator transfer function non-linearity and optical signal to noise ratio. Then hybrid modulation format is optimized to have maximum throughput. Using Monte Carlo simulation we compare optimized hybrid modulation format with standard DMT for different bit rates. Finally, we have a complexity comparison between hybrid and DMT for different fiber lengths to motivate same investigation for long-haul applications where, we should consider fiber non-linearity, attenuation, a polarization multiplexing.
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Dionísio, Rogério Pais. "Advanced optical modulation and format conversion." Doctoral thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/12850.
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Doutoramento em Engenharia ElectrotécnicaOver the years, the increased search and exchange of information lead to an increase of traffic intensity in todays optical communication networks. Coherent communications, using the amplitude and phase of the signal, reappears as one of the transmission techniques to increase the spectral efficiency and throughput of optical channels. In this context, this work present a study on format conversion of modulated signals using MZI-SOAs, based exclusively on all- optical techniques through wavelength conversion. This approach, when applied in interconnection nodes between optical networks with different bit rates and modulation formats, allow a better efficiency and scalability of the network. We start with an experimental characterization of the static and dynamic properties of the MZI-SOA. Then, we propose a semi-analytical model to describe the evolution of phase and amplitude at the output of the MZI-SOA. The model’s coefficients are obtained using a multi-objective genetic algorithm. We validate the model experimentally, by exploring the dependency of the optical signal with the operational parameters of the MZI-SOA. We also propose an all-optical technique for the conversion of amplitude modulation signals to a continuous phase modulation format. Finally, we study the potential of MZI-SOAs for the conversion of amplitude signals to QPSK and QAM signals. We show the dependency of the conversion process with the operational parameters deviation from the optimal values. The technique is experimentally validated for QPSK modulation.
Nos últimos anos, a crescente procura e troca de informação tem levado ao aumento de tráfego nas redes de comunicação óticas atuais. As comunicações coerentes, com recurso à amplitude e fase do sinal, ressurgem como uma das técnicas de transmissão capazes de aumentar a eficiência espectral e o rendimento dos canais óticos. Nesse âmbito, este trabalho apresenta um estudo sobre a conversão de formatos de modulação de sinais, usando técnicas exclusivamente no domínio ótico, através de conversão de comprimento de onda, com base no MZI-SOA. Esta técnica, aplicada em nós óticos que interligam redes óticas com débitos binários distintos, permite uma maior escalabilidade e eficiência da rede. A tese começa por apresentar uma caracterização experimental detalhada das propriedades estáticas e dinâmicas do MZI-SOA. É depois proposto um modelo semi-analítico que descreve a evolução da amplitude e fase do sinal ótico à saída do MZI-SOA. Os coeficientes do modelo são obtidos recorrendo a um algoritmo genético multiobjectivo. O modelo é validado experimentalmente, explorando a dependência do sinal ótico com os parâmetros operacionais do MZI- SOA. Segue-se a proposta de uma técnica de conversão de formato de modulação de amplitude para modulação de fase contínua. Finalmente, é feito um estudo das potencialidades do MZI-SOA para conversão de formato de modulação de amplitude para modulação QPSK e QAM. Mostra-se a dependência da constelação do sinal com o desvio dos parâmetros operacionais, em torno do valor ótimo. A técnica é validada experimentalmente para modulação QPSK.
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Srinivas, K. T. "Axial strain effects on optical fiber mode patterns." Thesis, This resource online, 1987. http://scholar.lib.vt.edu/theses/available/etd-04122010-083554/.
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Buyuksahin, Oncel F. Feza. "Modulation Formats For Wavelength Division Multiplexing (wdm) Systems." Phd thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12611039/index.pdf.
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Optical communication networks are becoming the backbone of both national and international telecommunication networks. With the progress of optical communication systems, and the constraints brought by WDM transmissions and increased bit rates, new ways to convert the binary data signal on the optical carrier have been proposed.
There are different factors that should be considered for the right choice of modulation format, such as information spectral density (ISD), power margin, and tolerance against group-velocity dispersion (GVD) and against fiber nonlinear effects like self-phase modulation (SPM), cross-phase modulation (XPM), four-wave mixing (FWM), and stimulated Raman scattering (SRS).
In this dissertation, the several very important modulation formats such as Non Return to Zero (NRZ), Return to Zero (RZ), Chirped Return to Zero (CRZ), Carrier Suppressed Return to Zero (CSRZ), Differential Phase Shift Keying (PSK) and Carrier Suppressed Return to Zero- Differential Phase Shift Keying (CSRZ-DPSK) will be detailed and compared.
In order to make performance analysis of such modulation formats, the simulation will be done by using VPItransmissionMakerTM WDM software.
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Luo, Haitao. "Snapshot Imaging Polarimeters Using Spatial Modulation." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/193905.
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The recent demonstration of a novel snapshot imaging polarimeter using the fringe modulation technique shows a promise in building a compact and moving-parts-free device. As just demonstrated in principle, this technique has not been adequately studied. In the effort of advancing this technique, we build a complete theory framework that can address the key issues regarding the polarization aberrations caused by using the functional elements. With this model, we can have the necessary knowledge in designing, analyzing and optimizing the systems. Also, we propose a broader technique that uses arbitrary modulation instead of sinusoidal fringes, which can give us more engineering freedom and can be the solution of achromatizing the system. In the hardware aspect, several important progresses are made. We extend the polarimeter technique from visible to middle wavelength infrared by using the yttrium vanadate crystals. Also, we incorporate a Savart Plate polarimter into a fundus camera to measure the human eye's retinal retardance, useful information for glaucoma diagnosis. Thirdly, a world-smallest imaging polarimeter is proposed and demonstrated, which may open many applications in security, remote sensing and bioscience.
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Alahmari, Abdallah Said. "Turbo coded pulse position modulation for optical communications." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/15388.
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An, Dechang. "Electro-optic polymer-based monolithic waveguide devices with multi-functions of amplification switching and modulation." Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3035933.
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Andrikogiannopoulos, Nikolas I. "RF phase modulation of optical signals and optical/electrical signal processing." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/42930.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 125-127).
Analog RF phase modulation of optical signals has been a topic of interest for many years, mainly focusing on Intensity Modulation Direct Detection (IMDD). The virtues of coherent detection combined with the advantages of Frequency Modulation, however, have not been explored thoroughly. By employing Frequency Modulation Coherent Detection (FMCD), the wide optical transmission bandwidth of optical fiber can be traded for higher signal-to-noise performance. In this thesis, we derive the FM gain over AM modulation -- the maximum achievable signal-to-noise ratio (by spreading the signal's spectrum) for specific carrier-to-noise ratio. We then employ FMCD for a scheme of remote antennas for which we use optical components and subsystem to perform signal processing such as nulling of interfering signals. The performance of optical processing on different modulation schemes are compared, and some important conclusions are reported relating to the use of conventional FMCD, FMCD with optical discriminator (FMCD O-D), and IMDD. Specifically, the superiority of conventional FMCD is shown; and, on the other hand, the inferiority of FMCD O-D is shown (same performance as IMDD) because of the use of an O-D. Finally, the remote antenna scheme is generalized for N antennas and N users.
by Nikolas I. Andrikogiannopoulos.
S.M.
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Thorn, Andrew Peter. "Electro-optical modulation in III-V semiconductors." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/46578.
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Jones, David Rhys. "Forward Error Correction in Memoryless Optical Modulation." UNF Digital Commons, 2011. http://digitalcommons.unf.edu/etd/171.
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The unprecedented growth in demand for digital media has led to an all-time high in society’s demand for information. This demand will in all likelihood continue to grow as technology such as 3D television service, on-demand video and peer-to-peer networking continue to become more common place. The large amount of information required is currently transmitted optically using a wavelength division multiplexing (WDM) network structure. The need to increase the capacity of the existing WDM network infrastructure efficiently is essential to continue to provide new high bandwidth services to end-users, while at the same time minimizing network providers’ costs. In WDM systems the key to reducing the cost per transported information bit is to effectively share all optical components. These components must operate within the same wavelength limited window; therefore it is necessary to place the WDM channels as close together as possible. At the same time, the correct modulation format must be selected in order to create flexible, cost-effective, high-capacity optical networks. This thesis presents a detailed comparison of Differential Quadrature Phase Shift Keying (DQPSK) to other modulation formats. This comparison is implemented through a series of simulations in which the bit error rate of various modulation formats are compared both with and without the presence of forward error correction techniques. Based off of these simulation results, the top performing modulation formats are placed into a multiplexed simulation to assess their overall robustness in the face of multiple filtering impairments.
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Lopes, Ana Patrícia da Silva. "Advanced modulation formats for optical access networks." Master's thesis, Universidade de Aveiro, 2013. http://hdl.handle.net/10773/11680.
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Mestrado em Engenharia Electrónica e TelecomunicaçõesNos últimos anos, as comunicações ópticas têm-se revelado a solução para a crescente procura de elevados ritmos de informação. De facto, nenhuma outra tecnologia (com ou sem fios) permite transmissões a Tbps, ou até dezenas de Tbps, como as comunicações ópticas permitem. Contudo, as actuais redes ópticas passivas não exibem uma capacidade agregada de fibra superior a 10 Gbps e os operadores esperam mais delas. Assim, uma evolução destas redes a médio prazo, a NG-PON2, tem sido discutida, sendo 40 e 10 Gbps as velocidades de download e upload que se preveem, respectivamente. Não obstante, estes ritmos podem não ser suficientes no futuro, com a emersão dos formatos 3D, dos novos serviços baseados em cloud computing, vídeo conferência, jogos on-line e outras/os aplicações/serviços. Neste contexto, diversos trabalhos de pesquisa têm sido efectuados. Devido á limitação do espectro e á largura de banda restrita dos dispositivos eletrónicos que complementam o sistema de transmissão óptico, elevadas eficiências espectrais são um requisito e consequentemente, a utilização de formatos de modulação avançados. A implementação intrínseca de detecção coerente e processamento digital de sinal proporcionam técnicas de compensação que melhoram o desempenho do sistema de uma forma muito significativa. Uma vez que, o crescente número de bits por símbolo exige uma maior relação sinal-ruído óptica e torna o sistema mais sensível ás não linearidades da fibra e ao ruído de fase do laser, estes algoritmos de compensação tornam-se essenciais. Esta dissertação fornece uma ampla visão dos sistemas ópticos coerentes que inclui, uma extensiva apresentação dos moduladores externos ópticos, um estudo teórico dos formatos de modulação e do formato do impulso, uma descrição de algoritmos de compensação e técnicas de detecção e finalmente, simulações e resultados laboratoriais que permitem concluir qual é o formato de modulação avançado mais indicado para transmissões ópticas a elevados ritmos.
In the last years, optical fibre communications have revealed themselves as the solution for the increasing demand of high data rates. In fact, no other communication technology (wireline or wireless) enables transmissions at Tbps, or even tens of Tbps, as optical communications do. However, the current passive optical networks do not exhibit aggregate fibre capacity beyond 10 Gbps and operators except more from them. Therefore, a middleterm evolution of these PONs, the NG-PON2, has been discussed, being 40 and 10 Gbps the predicted down- and upstream bit rates, respectively. Nevertheless, these rates upgrades may not be enough in the future, as 3D formats, new cloud computing services, videoconferencing, on-line games and alike applications/services become to emerge. In this context, much research is being carried on. Because of the limited spectrum and the restrict bandwidth of the electronic devices that complement the optical transmission system, high spectral efficiency is a requirement and consequently, the use of advanced modulation formats. The intrinsic employment of coherent detection and digital signal processing provides compensation techniques that increase hugely the performance of the system. Once the increasing number of bits per symbol requires higher optical signal-to-noise ratio and makes the system more sensitive to fibre nonlinearities and laser phase noise, these compensation algorithms become essential. This thesis provides an ample overview of coherent optical systems, which includes an extensive presentation of external modulators, a theoretical study of modulation formats and pulse shaping, a description of compensation algorithms and detection techniques and finally, simulations and laboratory results that will provide a conclusion about what is the most suited advanced modulation format for high data rates optical transmissions.
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Harrison, James Ashley. "All-optical processing using cross-phase modulation." Thesis, Aston University, 2005. http://publications.aston.ac.uk/8020/.
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The following thesis presents results obtained from both numerical simulation and laboratory experimentation (both of which were carried out by the author). When data is propagated along an optical transmission line some timing irregularities can occur such as timing jitter and phase wander. Traditionally these timing problems would have been corrected by converting the optical signal into the electrical domain and then compensating for the timing irregularity before converting the signal back into the optical domain. However, this thesis posses a potential solution to the problem by remaining completely in the optical domain, eliminating the need for electronics. This is desirable as not only does optical processing reduce the latency effect that their electronic counterpart have, it also holds the possibility of an increase in overall speed. A scheme was proposed which utilises the principle of wavelength conversion to dynamically convert timing irregularities (timing jitter and phase wander) into a change in wavelength (this occurs on a bit-by-bit level and so timing jitter and phase wander can be compensated for simultaneously). This was achieved by optically sampling a linearly chirped, locally generated clock source (the sampling function was achieved using a nonlinear optical loop mirror). The data, now with each bit or code word having a unique wavelength, is then propagated through a dispersion compensation module. The dispersion compensation effectively re-aligns the data in time and so thus, the timing irregularities are removed. The principle of operation was tested using computer simulation before being re-tested in a laboratory environment. A second stage was added to the device to create 3R regeneration. The second stage is used to simply convert the timing suppressed data back into a single wavelength. By controlling the relative timing displacement between stage one and stage two, the wavelength that is finally produced can be controlled.
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Zong, Jie. "Conversion efficiency improvement in acousto-optical modulation." Diss., The University of Arizona, 1999. http://hdl.handle.net/10150/298755.
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A high conversion efficiency in acousto-optical (AO) modulation can be obtained through careful design of an acousto-optic modulator (AOM), as well as careful selection of the following: the AO crystal material, the orientation in the AO crystal with respect to direction of propagation of the acoustic wave, the piezoelectric transducer material, the orientation of the transducer material, and the AOM fabrication method. A class of AOM's has been introduced wherein the diffraction efficiency of the AOM is improved by augmenting the design of the AOM so as to produce two or more passes of the optical beams through the acoustic beam wherein the Bragg diffraction conditions are satisfied. The effects of changes in acoustic beam direction and optical beam directions of propagation for the multiple-pass configuration are described in this dissertation. An AOM is fabricated in order to test the predicted properties of the class of AOM's incorporating the multiple-pass of optical beams for improving the conversion efficiency in AO modulation. Certain ones of the predicted properties of the multiple pass class of AOM's are confirmed by double pass experimental results for the fabricated AOM.
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Dumenil, Arnaud. "Polarization dependent loss in next-generation optical networks : challenges and solutions." Electronic Thesis or Diss., Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAS006.
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La demande de débit en augmentation constante requiert des canaux de communication fiables et robustes. Les réseaux optiques terrestres ainsi que les liens sous-marins représentent le cœur de l'infrastructure des télécommunications au niveau mondial, et transportent des centaines de canaux fréquentiels modulés à haut débit. Ces liens se composent non seulement de kilomètres de fibre mais aussi de composants optiques comme les amplificateurs à fibre dopée à l'erbium (EDFA) pour relever régulièrement la puissance des signaux atténués, ou encore des commutateurs sélectifs en longueur d'onde (WSS) qui routent le signal vers leur destination. Dans cette thèse, nous nous intéressons à une pénalité spécifique qui survient dans ces systèmes et qui réduit le débit d'information dans une propagation optique. Les composants optiques discrets présentent typiquement une anisotropie en polarisation : un déséquilibre de perte (ou gain) apparaît entre les deux polarisations d'un signal optique multiplexé en polarisation. Cet effet non unitaire appelé pertes dépendant de la polarisation (abrégé PDL en anglais) dégrade la qualité de transmission dans les systèmes optiques actuels et futurs.Dans le cadre des transmissions multiplexés en polarisation, nous caractérisons la perte de capacité induite par la PDL. Pour commencer, des modèles de canal sont attentivement étudiés et deux approches sont présentées : un canal avec des éléments PDL distribués avec un bruit également distribué, ou alors un canal équivalent simplifié en un seul élément. Nous analysons les limites fondamentales de communication associées à ces modèles. Nous montrons en outre que la capacité d'un canal PDL dépend en pratique de l'orientation de l'état de polarisation du signal incident. Nous passons ensuite en revue l'état de l'art de schémas de modulation atténuant l'effet de PDL puis nous proposons deux nouveaux schémas de modulation multi-dimensionnels qui augmentent la performance minimum et moyenne du canal. Ces deux modulations sont des transformations unitaires de symboles M-QAM qui n'utilisent pas de degrés de liberté autres que les quatre déjà utilisés pour chaque longueur d'onde (encodage en phase et quadrature de phase sur les deux états de polarisation). Nous proposons succinctement une extension de ces premiers résultats à des communications optiques plus généralement multiplexés en dimension spatiale et impactées par des pertes dépendantes de mode, qui présentent un déséquilibre de gain identique. Au-delà de la construction de modulations au niveau du transmetteur, nous étudions la perte de performance en présence de PDL d'une chaîne de traitement de signal conventionnelle et séquentielle par comparaison avec une égalisation et décodage joint. Cette perte additionnelle de capacité résultant du traitement séquentiel non optimal est évaluée pour différents formats de modulations ainsi que différents points de fonctionnement. Enfin, nous exposons une validation expérimentale des deux schémas de modulation proposés, aussi bien sur un élément de PDL seul ou sur un canal PDL distribué, et montrons comme attendu une robustesse augmentée vis-à-vis de la PDLLarge amounts of ever-increasing global data traffic require sound and reliable communication channels. Optical terrestrial networks and submarine links are at the very heart of the global telecom infrastructure, and carry hundreds of frequency channels modulated at very high rates. These links include not only kilometers of fiber but also optical elements such as Erbium-Doped Fiber-Amplifiers (EDFA) to amplify periodically the attenuated signals and Wavelength Selective Switches (WSS) to route the signals to their assigned destinations. In this thesis, we explore a specific rate-degrading impairment of the optical propagation that raises in those systems. Discrete optical elements often exhibit a polarization anisotropy that emerges as a gain or loss imbalance between the two polarization tributaries of the polarization-multiplexed optical signals. This non-unitary effect called Polarization Dependent Loss (PDL) impairs the quality of transmission in current and next-generation optical systems.In the context of polarization-multiplexed signals, we assess the capacity loss induced by PDL. First, channel models are carefully studied and two approaches are described: a channel with distributed PDL elements and distributed noise or a simplified single-element equivalent channel. Making use of these models, we then analyze their fundamental limits of communications. We show that the PDL channel capacity depends in practice on the state-of-polarization orientation of the incident signal. We then review the state-of-the art of PDL-mitigating modulation schemes and propose two new multi-dimensional signaling schemes that enhance worst-case and average performance. These two modulations are unitary transforms of M-QAM symbols and do not make use of additional degrees of freedom apart from the four already-used dimensions per wavelength (in-phase and quadrature channels of two polarization states). We briefly extend these first results to space-division-multiplexed optical communications impaired by mode dependent loss (MDL) that present a similar gain imbalance. Beyond signal shaping at the transmitter side, we study the performance loss of a conventional, sequential signal processing chain at the receiver side in presence of PDL, in comparison with a joint equalization-decoding scheme. The additional capacity loss due to the mismatch sequential processing is evaluated for several modulation formats and at different operating points. Finally, we report an experimental validation of the two proposed signaling schemes, both on a single PDL element and on a distributed PDL channel, demonstrating the predicted enhanced robustness to PDL
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Ireeta, Winston Tumps. "Aerial optical fibres in telecommunication systems : SOP and PMD monitoring, and tolerance of modulation formats." Thesis, Nelson Mandela Metropolitan University, 2010. http://hdl.handle.net/10948/1478.
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The topic of this thesis is aerial optical fibres in telecommunication systems: state of polarization (SOP) and polarization mode dispersion (PMD) monitoring and tolerance of modulation formats. Errors in optical fibre telecommunication systems are introduced when these polarization effects (SOP and PMD) change. These changes are so intense especially in aerial optical fibres. Part of the backbone of South Africa’s national grid includes long distances of aerial optical fibre between transmission exchange stations. The work in this thesis can be divided into three parts which all deal with the major aspects of PMD in deployed aerial optical fibres: characterization, environmental effects plus other perturbations, and tolerance of different modulation formats. In our work, SOP and PMD field measurements revealed that they both fluctuate more rapidly in deployed aerial optical fibres especially on windy and hot days. The SOP and PMD changes in the aerial optical fibres showed a significant correlation with these environmental parameters. SOP and PMD are stochastic in nature due to changes in the properties of the optical fibres and its positions because of both intrinsic and extrinsic perturbations. In our work, with only 184 PMD values measured and obtained by use of the FTB-5700 single-ended dispersion analyzer, the predicted theoretical Gaussian fit was obtained with a mean of 0.47 ps and standard deviation of 0.08 ps. This small standard deviation was justification for its robustness and accuracy. The statistical distributions for first-order polarization mode dispersion (FO-PMD) and second-order polarization mode dispersion (SO-PMD) for the first time were experimentally confirmed when measured using the FTB-5700 single-ended dispersion analyzer instrument for deployed aerial optical fibres. We were also able to determine the time scale over which to compensate FO-PMD in deployed aerial fibres using the directional time drift autocorrelation function method. It is slightly higher than 390 s for SOP measurements made on a particular windy and hot day. This is due to the fact that the changes of the PMD vector are known to be slower than the SOP changes. vi We also investigated the theoretical statistical distribution that corresponds to output SOP variations. The SOP variations can either be with wavelength (for buried fibre) or with time (for aerial fibre). Our results showed that the statistics of the relative SOP changes approached the distribution proposed by Foschini et al. (2000). Advanced optical modulation formats have become a key ingredient in the design of modern state-of-the-art wavelength-division-multiplexed (WDM) optical transmission systems. In our work, we investigated which of these advanced modulation formats is best suited for the South African network especially on systems that have links of aerial optical fibres. Keywords: aerial optical fibre, polarization mode dispersion (PMD), principal states of polarization (PSP), state of polarization (SOP), first-order PMD, second-order PMD.
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Wongpaibool, Virach. "Improvement of Fiber Optic System Performance by Synchronous Phase Modulation and Filtering at the Transmitter." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/26111.
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In this dissertation the performance of a novel variant of a return-to-zero (RZ) modulation format, based on square-wave phase modulation and filtering of a continuous-wave (CW) signal, is investigated and compared with various modulation formats considered in the literature. We call this modulation format continuous-wave square-wave (CWSW). With CWSW an RZ pulse train is generated by phase modulating the CW signal by a periodic square-wave phase function having an amplitude of and frequency of half the bit rate, and then filtering the signal. The filter performs phase-to-amplitude conversion, resulting in an alternate-sign RZ pulse train, which is shown to be resistant to fiber dispersion. The alternate-sign RZ pulse train is then amplitude modulated with the data before the transmission. Alternate signs between adjacent pulses makes this signal format robust to impairments caused by the optical fiber, similar to a conventional alternate-sign RZ signal format. However, the unique property of the CWSW signal format is that individual pulses can induce peak intensity enhancement (PIE), a phenomenon by which the peak of a pulse increases during the initial propagation in the presence of dispersion. The PIE in effect delays the decrease in the pulse peak, which represents the signal level for bit 1. Thus, the eye opening at the receiver is improved. An analytically tractable model is developed to explain the occurrence of the PIE, which cannot be achieved with a conventional pulse shape. The sources of performance degradations for different modulation formats in single-channel 40 Gb/s systems are also discussed in this dissertation. Various transmission system configurations of practical interest are considered and the performance of CWSW is compared with alternative modulation formats. It is found that the CWSW signal format performs significantly better than the other considered modulation formats in systems not employing dispersion compensation and is comparable to the others in dispersion-managed systems. Furthermore, the transmitter configuration of the CWSW signal format is simpler than the other approaches.Ph. D.
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Grelaud, Guillaume. "New electrochromic organometallic materials for light modulation." Phd thesis, Rennes 1, 2012. http://www.theses.fr/2012REN1S120.
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Au cours de cette thèse, de nouveaux complexes alcynyles du fer et du ruthénium ont été synthétisés et caractérisés. Ces composés ont été élaborés pour permettre l'électro-commutation de leurs propriétés en optique non linéaire (ONL) entre plusieurs états redox. Dans un premier temps, des unités hétéro-bimétalliques ferrocène-ruthénium ont été étudiées. Il a pu être démontré que ces unités, qui sont des complexes à valence mixte de classe II dans leur état mono-cationique, possèdent les propriétés électrochromiques requises pour leur incorporation dans des assemblages conjugués plus étendus et actifs en ONL. Dans un second temps, des complexes octupolaires possédant un espaceur central de type triphénylamine ou oxyde de triphénylphosphine ont été préparés. Dans le cas des premiers, un complexe octupolaire hexanucléaire à six états redox distincts a été obtenu tandis qu'avec les seconds, un espaceur plus ‟étendu” a été requis pour optimiser les propriétés optiques de ces assemblages. Un électrochromisme marqué a pu être observé en solution pour tous ces complexes. Finalement, d'autres assemblages organométalliques ont également été étudiés. Ainsi, la fonctionnalisation d'un groupement ferrocényl-alcynyl de ruthénium avec un alcyne vrai a permis de greffer cet ensemble dinucléaire original sur une surface de silicium, ouvrant la voie à l'obtention d'interfaces électro-commutables. Par ailleurs, le potentiel des complexes ferrocényl-allénylidènes du ruthénium pour moduler les propriétés optiques de ce chromophore à la fois par oxydation et par réduction a été mis en évidenceDuring this PhD, new iron and ruthenium alkynyl complexes have been synthesized and characterized. These complexes had been prepared in order to switch their nonlinear optical properties between their different redox states using an electrochemical process. Firstly, ferrocenyl ruthenium alkynyl units have been studied. It has been shown that these heterobimetallic units, which are class-II mixed-valent complexes in their mono-cationic state, possess all the required electrochromic properties for their incorporation into more extended and conjugated NLO active assemblies. Then, triphenylamine- and triphenylphosphine oxide-cored octupolar complexes had been prepared. In the first case, a hexanuclear complex with six distinct redox state had been obtained whereas in the second, an ‟extended” triphenylphosphine oxide core had been developed in order to optimize their optical properties. In both cases, a marked electrochromic behavior in solution of the complexes has been observed. Finally, other organometallic dinuclear assemblies have been explored. Thus, functionalization of the ferrocenyl ruthenium alkynyl synthons with a terminal alkynyl bond has allowed the grafting of this complex onto a silicon surface, paving the way for electroswitchable materials. Alternatively, the potential of ferrocenyl ruthenium allenylidene complexes to modulate the (nonlinear) optical properties using both oxidative and reductive processes has been demonstrated
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Pérez, Galacho Diego. "High speed optical modulation, advanced modulation formats and mode division multiplexing in Silicon photonics." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS194/document.
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La demande en bande passante des systèmes de communication optique ne cesse de croitre. Des débits de données de l’ordre de plusieurs centaines de TBit/s sont attendus dans un futur proche. La photonique silicium est une technologie majeure pour faire face à ces besoins croissants. Sa compatibilité avec les technologies CMOS permet naturellement une co-intégration photonique/électronique sur les mêmes circuits. A court terme, l’augmentation des débits de données dans les générations futures de système de communication optique passe par l’utilisation de formats de modulation avancés, et l’augmentation du nombre de bits par symbole transmis. A plus long terme, de nouvelles techniques de multiplexage sont nécessaires. Le multiplexage de modes est actuellement une solution attractive à l’étude dans ce but.Dans ce travail de thèse, différents moyens pour implémenter ces nouveaux systèmes de communication optiques sont étudiés au niveau de l’émetteur. Ces travaux incluent dans une première partie la modélisation, conception et caractérisation des modulateurs silicium. Dans une seconde partie, de nouveaux composants pour manipuler les modes sur circuits intégrés photoniques sont proposés, conçus et caractérisés, avec pour application le multiplexage de modes.Une nouvelle méthode a été proposée pour la modélisation des modulateurs optiques silicium. Cette méthode permet de réduire le temps de simulation de 2 ordres de grandeur, en maintenant un bon niveau de précision. En utilisant ce modèle, des modulateurs basés sur des diodes PN latérales et interdigitées ont été conçus pour fonctionner en bande O des communications optiques. Les résultats expérimentaux ont permis la mise en évidence de diagrammes de l’œil avec des taux d’extinction de 10 dB pour des modulations de type OOK (ON-OFF Keying) à 10Gbit/s. De plus des modulations de type BPSK (Binary Phase Shift Keying) ont également été démontrées à 10Gbit/s.De nouveaux convertisseurs de modes et multiplexeurs ont été proposés, conçus, fabriqués et caractérisés, pour être utilisés dans des systèmes de multiplexage modal. Les résultats expérimentaux ont permis de mettre en évidence des fonctionnements large bande passante avec de grands taux d’extinctionBandwidth demand in optical communication systems is continually growing. Data rate values in the order of several hundreds of TBps are expected in the near future. In order to cope with those expectations silicon based technologies are believed to be the best suited. Its naturally compatibility with CMOS easily enables the electronics and photonics co-integration. In the short-term the way increase data rates in next generation optical communication systems goes through using advanced modulation format and increase symbol rates. In the long-term view, new multiplexing techniques will be required. In this sense, mode division multiplexing is nowadays an attractive approach under consideration.In this Thesis work, the way to implement these new optical communication schemes is studied from the transmitter point of view. It includes, on a first part the modeling, design and characterization of silicon modulators. And in a second part, it includes the proposition, design and characterization of novel mode handling devices for mode division multiplexing.A new way of modeling silicon modulators has been developed. This new model permits to reduce the computation time of modulator analysis up to two orders of magnitude, while maintaining a good level of accuracy. Using the model, modulators based on lateral PN junctions and interdigitated PN junctions were designed to work in the O-Band of optical communications. Characterization work has been performed on these modulators with good results. Wide-open OOK (On Off Keying) eye diagrams with 10 dB extinction ratio were obtained at 10GBps. Furthermore, BPSK (Binary Phase Shift Keying) modulation was also demonstrated at 10GBps.New kind of mode converters and multiplexers, intended to work as mode division multiplexing subsystems have been proposed, designed, fabricated and characterized. Measured results show broad bandwidth operation with high extinction ratio
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HOLM, DAVID ALLEN. "QUANTUM THEORY OF MULTIWAVE MIXING (RESONANCE FLUORESCENCE, SATURATION SPECTROSCOPY, MODULATION, PHASE CONJUGATION, QUANTUM NOISE)." Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/187980.
Full textAbstract:
This dissertation formulates and applies a theory describing how one or two strong classical waves and one or two weak quantum mechanical waves interact in a two-level medium. The theory unifies many topics in quantum optics, such as resonance fluorescence, saturation spectroscopy, modulation spectroscopy, the build up of laser and optical bistability instabilities, and phase conjugation. The theory is based on a quantum population pulsation approach that resembles the semiclassical theories, but is substantially more detailed. Calculations are performed to include the effects of inhomogeneous broadening, spatial hole burning, and Gaussian transverse variations. The resonance fluorescence spectrum in a high finesse optical cavity is analyzed in detail, demonstrating how stimulated emission and multiwave processes alter the spectrum from the usual three peaks. The effects of quantum noise during the propagation of weak signal and conjugate fields in phase conjugation and modulation spectroscopy are studied. Our analysis demonstrates that quantum noise affects not only the intensities of the signal and conjugate, but also their relative phase, and in particular we determine a quantum limit to the semiclassical theory of FM modulation spectroscopy. Finally, we derive the corresponding theory for the two-photon, two-level medium. This yields the first calculation of the two-photon resonance fluorescence spectrum. Because of the greater number of possible interactions in the two-photon two-level model, the theoretical formalism is considerably more complex, and many effects arise that are absent in the one-photon problem. We discuss the role of the Stark shifts on the emission spectrum and show how the Rayleigh scattering is markedly different.
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Cryan, Robert Anthony. "High sensitivity optical digital pulse position modulation systems." Thesis, University of Huddersfield, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306086.
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Digital pulse position modulation (PPM) is a transmission format that can be used to exchange excess channel bandwidth for improved receiver sensitivity. This thesis is concerned with the performance of digital PPM for use in optical fibre systems such that increased single-span transmission distances can be achieved. It includes a literature survey and a thorough theoretical investigation into uncoded directly detected and coherently detected digital PPM, along with an evaluation of forward error correction coded PPM. Original contributions are described for digital PPM systems employing PIN-BJT transimpedance and PIN -FET high impedance pre-amplifiers. In the PIN -BJT case, a new analysis is presented that accounts for the band-limiting effect of the preamplifier and the non-white noise power spectral density, resulting from equalisation. For the PIN-FET, a causal noise-whitening filter is considered and the factors that limit the maximum bit-rate determined. By using an upper Chernoff Bound to the average binary error probability, results are calculated for APD-BJT and APD-FET PPM systems. The practical implementation of the optimal PPM filter is considered and two novel techniques are described for automating the realisation process. Coherent PPM is investigated and new work is presented for Reed-Solomon coded homodyne PPM. The influence of the Reed-Solomon code rate on receiver sensitivity is studied and it is shown that a 3/4 code rate leads to optimum sensitivity. Digital PPM employing soliton pulses is examined and it is shown that, under ideal conditions, a higher bit-rate than PCM can be achieved. The influence of timing jitter, associated with soliton pulse energy fluctuations and the Gordon-Haus effect, on the performance of digital PPM is investigated. The simplification of the PPM pre-detection filter is studied and a range of suboptimum filters investigated. The calculations demonstrate that the optimal predetection filter can be replaced by a simple 3rd order filter without incurring a severe sensitivity penalty. The sensitivity results of the various digital PPM systems investigated in this thesis are compared to those of equivalent PCM systems. It is illustrated that digital PPM offers an improvement of between 5-10 dB depending upon which coding format/ detection technique is employed. This represents an increase in transmission distance of 25-50 km and demonstrates that digital PPM is a promising modulation format and has potential for future high performance telecommunication routes.
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Fang, Yi-chin. "Performance evaluation of discrete IR optical system." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270211.
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Grennek, David S. "Amplitude modulation using a nonlinear optical loop mirror." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1998. http://handle.dtic.mil/100.2/ADA358980.
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Thesis (M.S. in Applied Physics) Naval Postgraduate School, December 1998."December 1998." Thesis advisor(s): Andres Larraza, H. Sarma Lakkaraju. Includes bibliographical references (p. 41). Also available online.
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Zeng, Yu. "Adaptive modulation schemes for optical wireless communication systems." Thesis, University of Warwick, 2010. http://wrap.warwick.ac.uk/3837/.
Full textAbstract:
High-speed wireless optical communication links have become more popular for personal mobile applications. This is a consequence of the increasing demand from the personal information service boom. Compared to the radio frequency domain, optical wireless communication offers much higher speeds and bit rates per unit power consumption. As stated by the official infrared standard IrDA optical communication enjoys much lower power consumption than Bluetooth, with an inherent security feature while in Line of Sight (LOS) applications. There are also drawbacks such as the infrared radiation cannot penetrate walls as radio frequencies do and interference from the background contribute to the channel dispersions. Focus on the modulation aspects of the optical wireless communication, this thesis try to improve the channel immunity by utilising optimised modulation to the channel. Modulation schemes such as on off keying (OOK), pulse amplitude modulation (PAM) and pulse position modulation (PPM) and pulse position and amplitude modulation PAPM schemes have been validated. The combined power and bandwidth requirements suggest that the adaptive modulation schemes can provide reliability when deployed in a real time channel, resulting in improved system performance. As a result, an adaptive modulation technique is proposed. Extensive simulations of severe noise distraction have been carried out to validate the new scheme. The simulation results indicate that the new scheme can provide increased immunity against channel noise fluctuation at a relatively low complexity. The scheme obtained formed a basis to support reliable mobile optical wireless communication applications. The adaptive scheme also takes the real time channel conditions into account, which is different from existing schemes. Guaranteed system performance can be secured without compromising power and bandwidth efficiency. This is also a new approach to realise reliable optical wireless links. Fuzzy logic control module has been developed to match the adaptive pattern.
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Kaluarachchi, Eraj Dulip. "Digital pulse interval modulation for optical communication systems." Thesis, Sheffield Hallam University, 1997. http://shura.shu.ac.uk/9101/.
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Pulse time modulation (PTM) techniques have drawn considerable attention over the years as suitable schemes for transmission of information over optical fibres. PTM schemes are known to utilise the vast optical bandwidth to provide efficient transmission characteristics. Pulse code modulation is one such modulation scheme that has been used widely in various communication systems. In this thesis digital pulse interval modulation (DPIM), a form of PTM, is proposed as a suitable modulation scheme for optical communication systems. In this scheme the information is represented by means of varying the anisochronous frame interval between two successive pulses. Each pulse fulfils the dual role of representing the frame boundaries and initiation of the next sampling event within the modulator or sample reconstruction in the demodulator. In this study DPIM frame structure is proposed and sampling criteria, information capacity, bandwidth requirements are discussed in depth. The spectral behaviour of the scheme is investigated and a mathematical model is developed to represent the spectra. The model was numerically evaluated and verified with the practical measurements to prove its validity. Spectral predictions were made for random as well as periodic information signals showing the existence of the distinct slot frequency component, which is used for slot synchronisation. Frame synchronisation is not required as DPIM has self synchronised frame structure. For random signals, slot component is found to be about 15 dB and for periodic single tone sinusoidal signal this was at about 5 dB. Dependency of this component on the various system parameters such as bit resolution, pulse width, pulse shape are discussed. A detailed account of the receiver performance is given. Receiver analysis was carried out for narrow band as well as for wide band channels. Possible error sources are presented and the system performance degradation with these error sources is discussed and a comparison is made with isochronous DPPM and PCM. For performance evaluation of analogue systems, signal-to-noise ratio was mathematically modelled and compared with PCM. This analysis showed that DPIM SNRs shows three important regions as compared to PCM. That is when the SNR is inferior, superior and identical to PCM performance. Threshold levels corresponding to the above regions vary depending on the system bit resolution. A prototype DPIM system was designed and implemented to transmit low speed analogue signal (≈15 kHz) at bit resolutions of 4, 5 and 6 where the slot frequencies are at 510, 990 and 1950 kHz, respectively. Measurements were carried out in order to verify the predicted performance. This results showed close agreement with the predicted. Receiver sensitivity of the prototype at bit error rate of 10-9 was found to be about -45.5 dBm at all three cases with transmitted average power of -28.8 dBm allowing high optical power budget. The signal-to-noise ratio threshold level of the system was at -47 dBm. Finally, linearity measurements of the overall system were made at the above bit resolutions and the quantitative and qualitative results are presented.
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Menon, Mahesh. "Analysis of modulation formats for optical wireless systems." Thesis, Northumbria University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434760.
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Calvert, N. "An optical fibre digital pulse position modulation system." Thesis, University of Huddersfield, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382254.
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Jones, Liam. "Synthesis and regeneration of advanced optical modulation formats." Thesis, University of Southampton, 2016. https://eprints.soton.ac.uk/419063/.
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This thesis explores all-optical regeneration techniques for advanced modulation formats with the overall aim of increasing the transmission reach of optical data links. In order to carry out this work, a number of tools were developed for the generation of advanced optical modulation formats. They included a combination of techniques involving the use of a delay line interferometer (DLI), time gating and coherent temporal superposition. A BPSK seed signal was used to generate QPSK (with a single DLI) and 16-QAM (with two concatenated DLIs) signals. The all-optical regeneration schemes studied in this thesis take several forms: phase preserving amplitude regeneration; phase only regeneration; and phase and amplitude regeneration, many of them including PSA configurations as building blocks. Firstly, phase preserving amplitude regenerators were numerically and/or experimentally investigated. A multilevel amplitude regenerator in a PSA configuration, which was based on parametric pump-saturation, was analysed. A highly nonlinear fibre based dual-pump degenerate scheme was used to effect amplitude regeneration on a 4-level amplitude shift keying signal. Another amplitude regeneration scheme, this time based on optical injection locking, was also experimentally analysed, transmitting a BPSK signal over a 600-km long dark bre link. Secondly, a wavelength converting PSA-based phase regenerator for an M-PSK signal was developed by coherently summing the conjugated signal with the (M - 1)th phase harmonic, where M is the number of modulated symbols in the signal. This regenerator offers flexibility of operating power and harmonic mixing coefficient. Both numerical and experimental studies prove the feasibility of the proposed scheme. Another proposed regenerator, operating at the gain minima in a PSA configuration and working by coherently summing the signal to the π phase shifted (M+1)th harmonic, offers squeezing in both the amplitude and phase of the input signal. The latter work of this thesis introduces a phase regenerator which is designed to target higher-order M-PSK signals using a (simpler) M/2-PSK PSA-based regenerator.
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Liu, Tao. "Advanced Coded Modulation for High Speed Optical Transmission." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/613291.
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In the recent years, the exponential Internet traffic growth projections place enormous transmission rate demand on the underlying information infrastructure at every level, from the long haul submarine transmission to optical metro networks. In recent years, optical transmission at 100 Gb/s Ethernet date rate has been standardized by ITU-T and IEEE forums and 400Gb/s and 1Tb/s rates per DWDM channel systems has been under intensive investigation which are expected to be standardized within next couple of years.To facilitate the implementation of 400GbE and 1TbE technologies, the new advanced modulation scheme combined with advanced forward error correction code should be proposed. Instead of using traditional QAM, we prefer to use some other modulation techniques, which are more suitable for current coherent optical transmission systems and can also deal with the channel impairments. In this dissertation, we target at improving the channel capacity by designing the new modulation formats. For the first part of the dissertation, we first describe the optimal signal constellation design algorithm (OSCD), which is designed by placing constellation points onto a two dimensional space. Then, we expand the OSCD onto multidimensional space and design its corresponding mapping rule. At last, we also develop the OSCD algorithm for different channel scenario in order to make the constellation more tolerant to different channel impairments. We propose the LLR-OSCD for linear phase noise dominated channel and NL-OSCD for nonlinear phase noise dominated channel including both self-phase modulation (SPM) and cross-phase modulation (XPM) cases. For the second part of the dissertation, we target at probability shaping of the constellation sets (non-uniform signaling). In the conventional data transmission schemes, the probability of each point in a given constellation is transmitted equally likely and the number of constellation sets is set to 2!. If the points with low energy are transmitted with larger probability then the others with large energy, the non- uniform scheme can achieve higher energy efficiency. Meanwhile, this scheme may be more suitable for optical communication because the transmitted points with large probabilities, which have small energy, suffer less nonlinearity. Both the Monte Carlo simulations and experiment demonstration of both OSCD and non-uniform signaling schemes indicate that our proposed signal constellation significantly outperforms QAM, IPQ, and sphere-packing based signal constellations.
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Batshon, Hussam George. "Coded Modulation for High Speed Optical Transport Networks." Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/194075.
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At a time where almost 1.75 billion people around the world use the Internet on a regular basis, optical communication over optical fibers that is used in long distance and high demand applications has to be capable of providing higher communication speed and re-liability. In recent years, strong demand is driving the dense wavelength division multip-lexing network upgrade from 10 Gb/s per channel to more spectrally-efficient 40 Gb/s or 100 Gb/s per wavelength channel, and beyond. The 100 Gb/s Ethernet is currently under standardization, and in a couple of years 1 Tb/s Ethernet is going to be standardized as well for different applications, such as the local area networks (LANs) and the wide area networks (WANs). The major concern about such high data rates is the degradation in the signal quality due to linear and non-linear impairments, in particular polarization mode dispersion (PMD) and intrachannel nonlinearities. Moreover, the higher speed transceivers are expensive, so the alternative approaches of achieving the required rates is preferably done using commercially available components operating at lower speeds.In this dissertation, different LDPC-coded modulation techniques are presented to offer a higher spectral efficiency and/or power efficiency, in addition to offering aggregate rates that can go up to 1Tb/s per wavelength. These modulation formats are based on the bit-interleaved coded modulation (BICM) and include: (i) three-dimensional LDPC-coded modulation using hybrid direct and coherent detection, (ii) multidimensional LDPC-coded modulation, (iii) subcarrier-multiplexed four-dimensional LDPC-coded modulation, (iv) hybrid subcarrier/amplitude/phase/polarization LDPC-coded modulation, and (v) iterative polar quantization based LDPC-coded modulation.
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LI, RIXIN. "mixed modulation format for future optical transmission systems." Doctoral thesis, Politecnico di Torino, 2016. http://hdl.handle.net/11583/2641453.
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Developing a flexible network to fully utilize the existing spectral resource is a hot topic in the novel paradigm of optical transmission systems. In this thesis, I analysed hybrid modulation formats as an effective technique for the implementation of flexible transponders that are capable of trading-off the delivered data rate by the light path quality of transmission with a finer granularity. The flexible transponder is an enabling technology to introduce the elastic paradigm in the state-of-the-art networks, while maintaining compatibility with the installed equipment, including fibers, mux-demux and ROADMs, as required by telecommunication operators willing to exploit fixed grid WDM transmission.
Time division hybrid modulation format (TDHMF) is presented as the first solution. Through combining two modulation formats in the time division, TDHMF can achieve arbitrary bit-per-symbol, and provide a huge amount of flexibilities to the network. A comprehensive theoretical assessment of the back-to-back performances is also introduced. In particular, four different transmitter operation strategies are proposed and evaluated. They are the constant power strategy, the same Euclidean distance strategy, the same BER strategy and the minimum BER strategy. Through the back-to-back performance comparison, the same BER strategy is chosen as the most promising strategy, mainly due to its comparable sensitivity performance and the potential of transponder simplification.
This thesis also prepared another solution, which is Flexible M-PAM modulation format (FlexPAM). It is a hybrid of different M-PAMs in all four quadrature of the optical field. Although it providing less flexibility compared to TDHMF, FlexPAM has its unique advantage in two main aspect. Firstly, the inherently time consistent frame structure feature of FlexPAM may require an identical and simple transponder, which is very crucial from the operators point of view. Secondly, from the network perspective, the operators can assign each quadrature of FlexPAM to a specific network tributary and select an M-PAM according to the actual network conditions. Similar to TDHMF, both general characterization and theoretical formulation are discussed in detail. Then, the back-to-back performance of FlexPAM, including the comparison of different transmitter strategies that similar to the one of TDHMF, has been fully studied. The same BER strategy again provided a negligible SNR penalty in contrast to the optimal strategy. At the same time, by using the same FEC code for both M-PAM, the same BER strategy may require a simpler signal processing procedure and reduce the complexity.
A subsequent work after the back-to-back analysis is the signal non-linear propagation evaluation of these two novel modulation formats. This thesis provide an extensive simulation analysis on the propagation of a Nyquist-WDM channel comb over an uncompensated and amplified fiber link. Due to the power unbalance in the time division (TDHMF) or in the polarization/quadrature (FlexPAM), the mixed modulation formats normally have some penalty against to the GN-model predictions. To improve their propagation performance, a simple polarization interleaving countermeasure is presented. It works well on TDHMF and has a significant impact on certain case of FlexPAM. Furthermore, the power ratio tuning is also proposed as an easy implemented and effective tool to improve the propagation performance. In the end, the propagation performance of both TDHMF and FlexPAM are compared in terms of the maximum reach versus system net bit rate, in addition, both with and without countermeasures conditions were considered. The results of this investigation showed that TDHMF has almost the same performance as the GN model predictions after the countermeasures employed. FlexPAM can provide a comparable propagation performance in contrast to the GN model predictions. Considering the advantages that mentioned before, the propagation performance of FlexPAM is acceptable.
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Jaiswal, Anshul. "Design and performance evaluation of FSO system with OSSK modulation scheme." Thesis, IIT Delhi, 2019. http://eprint.iitd.ac.in:80//handle/2074/8111.
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Ladner, Michael Christopher. "Optical modulator LM 0202 P characteristics : application to amplitude modulation of argon-ion laser." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1996. http://handle.dtic.mil/100.2/ADA313485.
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Hosseini, Seyedreza, and Kambiz Jamshidi. "Modulation efficiency enhancement of an optical phase modulator using one dimensional photonic crystal structures." SPIE, 2015. https://tud.qucosa.de/id/qucosa%3A35320.
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Slow light effect based rib silicon waveguide structures are studied in this paper to enhance modulation efficiency of an optoelectronic carrier plasma dispersion effect based phase modulator. Center frequency to achieve desired slow down factor and band width limitations of the structures are investigated through finite element method simulations. Optical modulation efficiency is modeled and the effects of doping, bias voltage and slow light on its performance are studied.
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Debnath, Kapil. "Photonic crystal cavity based architecture for optical interconnects." Thesis, University of St Andrews, 2013. http://hdl.handle.net/10023/3870.
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Today's information and communication industry is confronted with a serious bottleneck due to the prohibitive energy consumption and limited transmission bandwidth of electrical interconnects. Silicon photonics offers an alternative by transferring data optically and thereby eliminating the restriction of electrical interconnects over distance and bandwidth. Due to the inherent advantage of using the same material as that used for the electronic circuitry, silicon photonics also promises high volume and low cost production plus the possibility of integration with electronics. In this thesis, I introduce an all-silicon optical interconnect architecture that promises very high integration density along with very low energy consumption. The basic building block of this architecture is a vertically coupled photonic crystal cavity-waveguide system. This vertically coupled system acts as a highly wavelength selective filter. By suitably designing the waveguide and the cavity, at resonance wavelength of the cavity, large drop in transmission can be achieved. By locally modulating the material index of the cavity electrically, the resonance wavelength of the cavity can be tuned to achieve modulation in the transmission of the waveguide. The detection scheme also utilizes the same vertically coupled system. By creating crystal defects in silicon in the cavity region, wavelength selective photodetection can be achieved. This unique vertical coupling scheme also allows us to cascade multiple modulators and detectors coupled to a single waveguide, thus offering huge channel scalability and design and fabrication simplicity. During this project, I have implemented this vertical coupling scheme to demonstrate modulation with extremely low operating energy (0.6 fJ/bit). Furthermore, I have demonstrated cascadeability and multichannel operation by using a comb laser as the source that simultaneously drives five channels. For photodetection, I have realized one of the smallest wavelength selective detector with responsivity of 0.108 A/W at 10 V reverse bias with a dark current of 9.4 nA. By cascading such detectors I have also demonstrated a two-channel demultiplexer.
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Zhao, Lu. "Optical transmission of wideband video signals using SWFM." Thesis, University of Manchester, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317775.
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Kamdar, Ketan Dilip. "Terfenol based optical phase modulator and magnetometer." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06302009-040256/.
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Detwiler, Thomas Frederick. "Continuous phase modulation for high speed fiber-optic links." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42867.
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Fiber-optic networks are continually evolving to accommodate the ever increasing data rates demanded by modern applications and devices. The current state-of-the art systems are being deployed with 100 Gb/s rates per wavelength while maintaining the 50 GHz channel spacing established for 10 Gb/s dense wavelength division multiplexed (DWDM) systems. Phase modulation formats (in particular quadrature phase shift keying - QPSK) are necessary to meet the spectral efficiency (SE) requirements of the application. The main challenge for phase modulated optical systems is fiber nonlinearities, where changes in intensity of the combined optical signal result in changes to the fiber's refractive index. Limiting launch power is the primary means to avoid dramatic intensity fluctuations, a strategy which in turn limits the available signal-to-noise ratio (SNR) within the channel.
Continuous phase modulation (CPM) is a format in which data is encoded in the phase, while the amplitude is constant throughout all transmission (even during transitions between symbols). With the goal of reducing the impact of nonlinearities, the purpose of this research was to identify a set of CPM signals best suited for high speed fiber-optic transmission, and quantify their performance against other formats. The secondary goal was to identify techniques appropriate for demodulation of high speed fiber-optic systems and implement them for simulation and experimental research.
CPM encompasses a number of variable parameters that combine to form an infinite number of unique schemes, each of which is characterized by its own SE, minimum distance, and implementation complexity. A method for computing minimum distance of DWDM-filtered CPM formats is presented and utilized to narrow down to a range of candidate schemes. A novel transmitter design is presented for CPM signal generation, as well as a number of novel reception techniques to achieve proper demodulation of the CPM signal from the coherent optical receiver. Using these methods, the identified range of candidate schemes was compared in simulation to the conventional QPSK format, showing that some modest gain can be expected from CPM.
Through these and other simulations, it is revealed that fiber nonlinearities depend on the aggregate sum of all wavelengths rather than the imposition of each separate carrier on its neighbors. Therefore the constant envelope of CPM does not directly impact the nonlinearities since multiple carriers will photonically interfere and result in intensity fluctuations regardless of modulation format. Additionally, dispersive effects in fiber decompose the underlying channels so that the intensity throughout propagation is nearly Gaussian distributed, regardless of format. The benefits gained from CPM are thus limited to schemes that attain a higher minimum distance than alternative formats (in the given channel passband), and for optically compensated links in which low dispersion is maintained throughout the fiber link.
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Li, Jun. "Ultrasound-modulated optical tomography for biomedical applications." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1274.
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I experimentally studied ultrasound-modulated optical tomography, which holds the promise for biomedical diagnosis. I measured the degree of polarization of laser speckles generated by scattered light transmitted through turbid media, investigated three signal-detection schemes for extracting the intensity of the ultrasound-modulated light, carried out experiments to image thick biological-tissue samples, and studied two techniques providing resolution in the cross-sections containing the ultrasonic axis.
The study of degree of polarization presented results important for the understanding of polarization phenomena in turbid media. I explored an optical-filtering based signal detection scheme, improved the parallel-lock-in speckle detection scheme and proposed a speckle-contrast detection scheme. With the speckle-contrast detection scheme, I successfully obtained images of biological-tissue samples up to 50 mm thick. Further I studied frequency-swept ultrasound-modulated optical tomography for sub-millimeter resolution imaging, and developed ultrasound-modulated optical computed tomography that was based on a back-projection image reconstruction method and obtained clear images of biological-tissue samples.
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Tsonev, Dobroslav Antonov. "High speed energy efficient incoherent optical wireless communications." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/10571.
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The growing demand for wireless communication capacity and the overutilisation of the conventional radio frequency (RF) spectrum have inspired research into using alternative spectrum regions for communication. Using optical wireless communications (OWC), for example, offers significant advantages over RF communication in terms of higher bandwidth, lower implementation costs and energy savings. In OWC systems, the information signal has to be real and non-negative. Therefore, modifications to the conventional communication algorithms are required. Multicarrier modulation schemes like orthogonal frequency division multiplexing (OFDM) promise to deliver a more efficient use of the communication capacity through adaptive bit and energy loading techniques. Three OFDM-based schemes – direct-current-biased OFDM (DCO-OFDM), asymmetrically clipped optical OFDM(ACO-OFDM), and pulse-amplitude modulated discrete multitone (PAM-DMT) – have been introduced in the literature. The current work investigates the recently introduced scheme subcarrier-index modulation OFDM as a potential energy-efficient modulation technique with reduced peak-to-average power ratio (PAPR) suitable for applications in OWC. A theoretical model for the analysis of SIM-OFDMin a linear additive white Gaussian noise (AWGN) channel is provided. A closed-form solution for the PAPR in SIM-OFDM is also proposed. Following the work on SIM-OFDM, a novel inherently unipolar modulation scheme, unipolar orthogonal frequency division multiplexing (U-OFDM), is proposed as an alternative to the existing similar schemes: ACO-OFDMand PAM-DMT. Furthermore, an enhanced U-OFDMsignal generation algorithm is introduced which allows the spectral efficiency gap between the inherently unipolar modulation schemes – U-OFDM, ACO-OFDM, PAM-DMT – and the conventionally used DCO-OFDM to be closed. This results in an OFDM-based modulation approach which is electrically and optically more efficient than any other OFDM-based technique proposed so far for intensity modulation and direct detection (IM/DD) communication systems. Non-linear distortion in the optical front-end elements is one of the major limitations for high-speed communication in OWC. This work presents a generalised approach for analysing nonlinear distortion in OFDM-based modulation schemes. The presented technique leads to a closed-form analytical solution for an arbitrary memoryless distortion of the information signal and has been proven to work for the majority of the known unipolar OFDM-based modulation techniques - DCO-OFDM, ACO-OFDM, PAM-DMT and U-OFDM. The high-speed communication capabilities of novel Gallium Nitride based μm-sized light emitting diodes (μLEDs) are investigated, and a record-setting result of 3.5Gb/s using a single 50-μm device is demonstrated. The capabilities of using such devices at practical transmission distances are also investigated, and a 1 Gb/s link using a single device is demonstrated at a distance of up to 10m. Furthermore, a proof-of-concept experiment is realised where a 50-μm LED is successfully modulated using U-OFDM and enhanced U-OFDM to achieve notable energy savings in comparison to DCO-OFDM.
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Kim, Dong Kwon. "Optical properties of asymmetric double quantum wells and optimization for optical modulators." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22649.
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Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008.Committee Chair: Citrin, David; Committee Member: Dupuis, Russell; Committee Member: Gaylord, Thomas; Committee Member: Rhodes, William; Committee Member: Zhang, Zhuomin.
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Elayoubi, Karim. "Study of communications channels for optical links through the atmosphere." Thesis, Toulouse, ISAE, 2019. http://www.theses.fr/2019ESAE0016/document.
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Les télécommunications optiques en espace libre pour les applications satellites deviennent unealternative aux communications radiofréquences pour les liens feeder (segment Satellite-Gateway) quicommencent à présenter une saturation en termes de bande passante avec une faible capacité desliaisons. Ces liaisons optiques présentent des avantages majeurs notamment une large bande passantedisponible, l’insensibilité aux interférences ou encore l’absence de régulation (pas de coût lié àl’utilisation de telle ou telle bande de longueur d’onde a contrario de la RF). Elles sont envisagées pourles futurs systèmes satellitaires utilisant des satellites en orbites géostationnaires (GEO : GeostaionaryOrbit) ou des orbites terrestres basses (LEO : Low Earth Orbit) afin d’augmenter la capacité desdonnées transmises. L’architecture des terminaux (OGS et satellites) et la modulation optique utiliséesont déterminantes pour la robustesse d’une telle liaison aux effets induits par les couches del’atmosphère. Bien que des expérimentations aient démontré la faisabilité de ce type de solution pourles télécommunications par satellites à des débits de l’ordre du Gb/s, des travaux de recherche sontencore nécessaires pour identifier les solutions techniques adaptées à ce nouveau médium detransmission et développer des émetteurs et récepteurs pouvant supporter des débits allant jusqu’à1Tb/s. Les travaux menés au cours de cette thèse ont pour objectif de développer des architecturesdes liaisons optiques utilisant différents formats de modulation afin de maitriser le comportement desrécepteurs après propagation atmosphérique (lien montant et lien descendant). Après avoir simulé laliaison avec un logiciel dédié à l’optique, un banc expérimental émulant le lien laser atmosphérique aété développé. Dans les deux cas, l’impact des effets atmosphériques a été pris en compte. Latraversée des couches de l’atmosphère présente des variations brusques d’atténuation dues auxturbulences atmosphériques qui agissent directement sur l’indice de réfraction affectant l’amplitudeet la phase du signal optique (on parle aussi des effets de scintillation). Il en résulte potentiellementdes pertes de paquets d’informations. Différents scénarii de perturbations atmosphériques (Faibleturbulences, Beam Wander, Fortes turbulences) ont été appliqués pour simuler numériquementchaque modèle de canal de communication. Le développement du banc ELLA (Emulateur Lien LaserAtmosphérique) a été réalisé pour émuler la traversée des couches atmosphériques et pour validerexpérimentalement en laboratoire les différents scénarii simulés numériquement. Le taux d’erreurbinaire (BER, Bit Error Rate) a été estimé avec et sans effet de fading induit par l’atmosphère dansdifférentes conditions de turbulences atmosphériques afin de déterminer les caractéristiques desliaisons optiques les plus robustesDue to expected capacity bottlenecks of exploited microwave technologies, feeder links for data relayor broadband access systems will require the implementation of high capacity optical communicationlinks between space and the ground. In this context, it is necessary to detail the investigation of theoptical technologies and techniques that could enable the transmission of high data rates at opticalfrequencies through the Earth’s atmosphere, with regard to all kinds of the atmospheric phenomena.In particular, the adverse effects of atmospheric turbulence fading are of special relevance to opticalcommunication systems for ground-to-space uplink applications. Although previous studies andexperiments have demonstrated the feasibility of such optical links at low data rate, research is stillneeded to identify technical solutions and strategies adapted to the specific constraints imposed tothese high-speed links in order to ensure the required level of performance. Against this background,various test benches have been developed to characterize different modulations and detectiontechniques for optical communication systems prior to be incorporated in the conceptual design offuture 1-Tb/s ground-space optical links. The expected performances of such experimentaldemonstration are derived based on simulation models taking into account the atmosphericturbulence effects, in order to prove the feasibility of reliable ground-to-space high date rate opticalcommunication links. The main objective of this thesis is the investigation of the free space opticalcommunication through the atmosphere under different turbulence regimes. Both simulation andexperimental demonstrations of such communications are considered and the associated results aredetailed