Narrowband optical filtering and chromatic dispersion are two important issues that affect optical fiber transmission performance. Recent technological developments in high-speed digital signal processors, digital-to-analog converters and analog-to-digital converters have enabled the implementation of electronic signal processing (ESP) in optical transmission systems leading to adaptive and cost efficient integrated solutions. This thesis focuses on applying ESP at the transmitter to pre-compensate for narrowband optical filtering and chromatic dispersion. A novel electronic pre-compensation approach was proposed to deal with narrowband optical filtering. The effectiveness was demonstrated by a straight-line experiment and a recirculating loop experiment for 10 Gb/s non-return-to-zero on-off-keying (NRZ-OOK). Moreover, the work was extended to NRZ differential-phase-shift-keying as well as 20 Gb/s NRZ differential-quadrature-phase-shift-keying. Experimental results demonstrate that electronic pre-compensation effectively reduces the degradation in system performance induced by narrowband optical filtering. Electronic dispersion pre-compensation was investigated using a semiconductor InP Mach-Zehnder modulator (MZM) for the NRZ-OOK modulation format at 10.709 Gb/s aiming at providing a cost efficient implementation for core and metro transmission networks. A brute-force method was developed to determine the requisite drive i voltages due to the nonlinear voltage dependent attenuation and phase constants of the InP MZM. The transmission results for the recirculating loop and straightline experiments demonstrate that an InP MZM provides comparable dispersion precompensation performance with a conventional LiNbO3 MZM. Use of the NRZ-OOK modulation format and InP MZM provides a simple and cost-efficient solution for core and metro transmission network. Dispersion pre-compensation was also performed for a 85.672 Gb/s polarization multiplexed 16-ary quadrature amplitude modulation (PM-16QAM) modulation format with digital coherent detection and offline digital signal processing. The transmitter was characterized to ensure the quality of the 16QAM signal generation. Simulation results indicate the impact of the modulator bias voltage error on system performance. Recirculating loop experimental results demonstrate that the performance of dispersion pre-compensation is comparable with dispersion post-compensation, thus providing the possibility to combine dispersion pre- and post-compensation for PM- 16QAM coherent transmission for further performance improvement. / Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2011-10-29 13:01:01.347

Coherent optical data processing is recognised, for many applications, as a viable alternative to digital electronic signal processing; the case for using coherent optics is particularly strong when the data to be processed is two dimensional in nature. It has long been accpeted that, in order for coherent optical processing to achieve its full performance potential, two dimensional spatial light modulators - capable of operating in real time - are essential at both the object plane (where the data is input to the system) and the Fourier plane (where the operation carried out on the data is determined). Most previous research in the field of spatial modulators has concentrated on optically addressed devices for use in the object plane. This thesis describes a prototype liquid crystal over silicon spatial light modulator built to test the feasibility of using such devices in a coherent optical processor. Optically, the device operates as a binary amplitude modulator, consisting of a square array of 16x16 pixels, each of size 100x100 m^2 and located at 200m centres. The integrated circuit is designed for a 6m wafer fabrication process. Each pixel of the IC contains a static memory element (which stores a digital logic voltage corresponding to the optical state of that pixel) and provides a stable square wave voltage signal to drive the liquid crystal layer. The component parts of the spatial light modulator are tested individually: the liquid crystal, in test cells, for contrast and switching speed; the IC for electrical performance and optical (flatness) characteristics. The effect of pixellation on optical performance is investigated. The performance of live devices is demonstrated. The results indicate the feasibility of using such a device as a binary amplitude spatial light modulator.

O trabalho tem por objetivo o estudo e o desenvolvimento de interferômetros recuperadores com baixa tensão de meia onda utilizando moduladores eletro-ópticos para serem aplicados em sistemas Interferométricos de luz branca. Ele dá continuidade às pesquisas do autor em seu mestrado, em que foi desenvolvido e testado um sistema de sensoriamento eletro-óptico capaz de medir diretamente tensões de até 69,4 kVRMS. Desta forma aperfeiçoa-se o sistema de processamento de sinais ópticos desenvolvendo um novo interferômetro recuperador, baseado em óptica integrada. Para o desenvolvimento do tema proposto, inicialmente foi feito uma revisão da literatura/bibliografia, baseada em livros, artigos e teses, visando identificar o \"estado da arte\" relacionado aos moduladores eletro-ópticos para definir o tipo de modulador mais adequado à aplicação em vista. O estudo resultou na escolha de um componente em óptica integrada que foi aplicado numa configuração inédita em um protótipo de transformador de potencial óptico para medição de elevados níveis de tensão elétrica. As características de desempenho deste protótipo foram comparadas com as do protótipo previamente construído. Como resultado deste trabalho, amplia-se o conhecimento e fixa-se em âmbito nacional o domínio sobre as técnicas de construção de interferômetros recuperadores baseados em óptica integrada aplicáveis à recuperação de sinais ópticos em sistemas interferométricos para medição de altas tensões. / This work has as objective the study and development of low half-wave voltage recovery interferometers using electro-optical modulators to be applied to white light interferometric systems. This work is a continuation in the research carried out by the author to obtain his master degree, in which it was developed and tested an electro- optic sensing system capable to measure direct voltage to 69.4 kVrms. In the present work the optical signals processing system is improved by developing a new recovery interferometer based on integrated optics. To develop the proposed subject, initially a review of the literature, based on books, articles and thesis, has been done aiming to identify the State of the Art related to electro-optic modulators and helping to define the most suitable type of modulator for the desired application. The study resulted in the selection of an integrated optical device arranged in an unpublished configuration that was applied to a prototype of optical voltage transformer, intended to measure high voltage levels. The performance of this prototype was compared with a previous version. The results of this work increase the knowledge of the construction techniques of recovery interferometers based on integrated optic devices applicable to the recovering of optical signals in interferometric systems for high voltage measurement.

O trabalho tem por objetivo o estudo e o desenvolvimento de interferômetros recuperadores com baixa tensão de meia onda utilizando moduladores eletro-ópticos para serem aplicados em sistemas Interferométricos de luz branca. Ele dá continuidade às pesquisas do autor em seu mestrado, em que foi desenvolvido e testado um sistema de sensoriamento eletro-óptico capaz de medir diretamente tensões de até 69,4 kVRMS. Desta forma aperfeiçoa-se o sistema de processamento de sinais ópticos desenvolvendo um novo interferômetro recuperador, baseado em óptica integrada. Para o desenvolvimento do tema proposto, inicialmente foi feito uma revisão da literatura/bibliografia, baseada em livros, artigos e teses, visando identificar o \"estado da arte\" relacionado aos moduladores eletro-ópticos para definir o tipo de modulador mais adequado à aplicação em vista. O estudo resultou na escolha de um componente em óptica integrada que foi aplicado numa configuração inédita em um protótipo de transformador de potencial óptico para medição de elevados níveis de tensão elétrica. As características de desempenho deste protótipo foram comparadas com as do protótipo previamente construído. Como resultado deste trabalho, amplia-se o conhecimento e fixa-se em âmbito nacional o domínio sobre as técnicas de construção de interferômetros recuperadores baseados em óptica integrada aplicáveis à recuperação de sinais ópticos em sistemas interferométricos para medição de altas tensões. / This work has as objective the study and development of low half-wave voltage recovery interferometers using electro-optical modulators to be applied to white light interferometric systems. This work is a continuation in the research carried out by the author to obtain his master degree, in which it was developed and tested an electro- optic sensing system capable to measure direct voltage to 69.4 kVrms. In the present work the optical signals processing system is improved by developing a new recovery interferometer based on integrated optics. To develop the proposed subject, initially a review of the literature, based on books, articles and thesis, has been done aiming to identify the State of the Art related to electro-optic modulators and helping to define the most suitable type of modulator for the desired application. The study resulted in the selection of an integrated optical device arranged in an unpublished configuration that was applied to a prototype of optical voltage transformer, intended to measure high voltage levels. The performance of this prototype was compared with a previous version. The results of this work increase the knowledge of the construction techniques of recovery interferometers based on integrated optic devices applicable to the recovering of optical signals in interferometric systems for high voltage measurement.