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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

On optical-signal-to-noise ratio and polarization-mode-dispersion monitoring in optical networks.

January 2004 (has links)
Man-Hong Cheung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 88-97). / Abstracts in English and Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Drivers for Advanced Optical Performance Monitoring (OPM) Techniques --- p.1 / Chapter 1.2 --- OPM: Definition and Significance --- p.4 / Chapter 1.3 --- The Broad Spectrum of OPM --- p.5 / Chapter 1.3.1 --- Signal Loss Monitoring --- p.7 / Chapter 1.3.2 --- Signal Alignment Monitoring --- p.7 / Chapter 1.3.3 --- Signal Quality Monitoring --- p.7 / Chapter 1.4 --- Classification of OPM Techniques --- p.9 / Chapter 1.4.1 --- Time Domain vs. Frequency Domain Monitoring --- p.9 / Chapter 1.4.2 --- Analog Parameter vs. Digital Parameter Monitoring --- p.9 / Chapter 1.4.3 --- Three-Tier OPM --- p.11 / Chapter 1.5 --- Challenges and Requirements of OPM Techniques --- p.13 / Chapter 1.6 --- Thesis Outline --- p.15 / Chapter Chapter 2 --- Review on OSNR and PMD Monitoring --- p.16 / Chapter 2.1 --- Optical Signal-to-Noise-Ratio (OSNR) Monitoring --- p.16 / Chapter 2.2 --- Out-of-band OSNR Monitoring Techniques --- p.17 / Chapter 2.2.1 --- Optical Spectral Analysis --- p.17 / Chapter 2.2.2 --- Arrayed Waveguide Grating/Tunable Filter Assisted Power Measurements --- p.19 / Chapter 2.2.3 --- RF Spectral Analysis --- p.20 / Chapter 2.2.3.1 --- Low/High RF Noise Monitoring --- p.20 / Chapter 2.2.3.2 --- Subcarrier CNR Correlation --- p.20 / Chapter 2.3 --- In-band OSNR Monitoring Techniques --- p.20 / Chapter 2.3.1 --- Polarization-Assisted OSNR Monitoring --- p.21 / Chapter 2.3.1.1 --- Polarization Extinction Method --- p.21 / Chapter 2.3.1.2 --- Polarization-Nulling --- p.22 / Chapter 2.3.1.3 --- Degree-of-Polarization (DOP) Based OSNR Monitoring --- p.23 / Chapter 2.3.2 --- In-band RF Spectral Analysis --- p.24 / Chapter 2.3.2.1 --- Orthogonal Delayed Homodyne Method --- p.24 / Chapter 2.3.2.2 --- Half Clock Frequency Constellation Monitoring / Chapter 2.3.3 --- Interferometric Approach --- p.26 / Chapter 2.3.4 --- Nonlinear Method --- p.26 / Chapter 2.4 --- Polarization-Mode-Dispersion (PMD) Monitoring --- p.27 / Chapter 2.4.1 --- Degree-of-Polarization (DOP) Monitoring --- p.29 / Chapter 2.4.2 --- RF Spectral Analysis --- p.31 / Chapter 2.4.2.1 --- PMD-Induced RF Dip Power Measurement --- p.31 / Chapter 2.4.2.2 --- Subcarriei-Based RF Power Fading Measurement --- p.32 / Chapter 2.4.3 --- "Eye-Opening, Penalty Monitoring" --- p.33 / Chapter 2.4.4 --- Phase Diversity Detection --- p.33 / Chapter 2.4.5 --- Arrival Time Measurement of Polarization-Scrambled Light --- p.34 / Chapter 2.4.6 --- Nonlinear Method --- p.34 / Chapter 2.5 --- Summary of different OSNR and PMD Monitoring Methods . --- p.34 / Chapter Chapter 3 --- On Robustness of In-band Polarization-Assisted OSNR Monitoring Techniques against PMD --- p.36 / Chapter 3.1 --- Introduction --- p.36 / Chapter 3.2 --- Impact of PMD on Polarization-Nulling --- p.37 / Chapter 3.2.1 --- Numerical Results using Ideal Rectangular Pulse --- p.40 / Chapter 3.2.2 --- Numerical and Experimental Results using Super Gaussian Pulse --- p.43 / Chapter 3.3 --- Impact of PMD on DOP-based OSNR Monitoring --- p.46 / Chapter 3.3.1 --- Numerical and Experimental Results Using Ideal Rectangular and Super-Gaussian Pulses --- p.46 / Chapter 3.4 --- Impact of PMD on Orthogonal Delayed-Homodyne Method --- p.49 / Chapter 3.5 --- Summary --- p.53 / Chapter Chapter 4 --- PMD-Insensitive OSNR Monitoring Based on Polarization-Nulling with Off-Center Narrowband Filtering --- p.54 / Chapter 4.1 --- Introduction --- p.54 / Chapter 4.2 --- Previously Proposed Schemes based on Polarization-Nulling --- p.55 / Chapter 4.2.1 --- Improved Polarization-Nulling Technique --- p.55 / Chapter 4.2.2 --- Periodic Polarization Encoding Technique --- p.57 / Chapter 4.3 --- A new PMD-Insensitive OSNR Monitoring Technique based on Polarization-Nulling with Off-Center Narrowband Filtering --- p.58 / Chapter 4.3.1 --- Principle of Proposed Technique --- p.59 / Chapter 4.3.2 --- Theoretical Calculations --- p.62 / Chapter 4.3.3 --- Experimental Results --- p.65 / Chapter 4.3.4 --- "Effects of Filter Position, Filter Bandwidth, and Filter Detuning" --- p.69 / Chapter 4.4 --- Summary --- p.71 / Chapter Chapter 5 --- Simultaneous OSNR and PMD Monitoring using Polarization Techniques --- p.72 / Chapter 5.1 --- Introduction --- p.72 / Chapter 5.2 --- Previously Proposed Scheme --- p.72 / Chapter 5.3 --- Simultaneous OSNR and PMD Monitoring by Enhanced RF Spectral Analysis --- p.74 / Chapter 5.3.1 --- Proposed Scheme --- p.75 / Chapter 5.3.2 --- Experimental Results --- p.77 / Chapter 5.4 --- DOP-based Simultaneous OSNR and PMD Monitoring --- p.80 / Chapter 5.4.1 --- Principle of Operation --- p.81 / Chapter 5.4.2 --- Experimental Results --- p.82 / Chapter 5.5 --- Summary --- p.84 / Chapter Chapter 6 --- Conclusions and Future Works --- p.85 / Chapter 6.1 --- Summary of the Thesis --- p.85 / Chapter 6.2 --- Future Works --- p.86 / Bibliography --- p.88 / Appendix - List of publications --- p.97
2

Design and applications of advanced optical modulation formats for optical metro/access transmission systems.

January 2012 (has links)
光纖通信技術與光網絡在過去三十年間極大地改變了人們的生活。雖然整個光通信行業因為2000年互聯網泡沫的破滅受到了影響,但近年來由於高清電視,移動多媒體和社交網絡的興盛,互聯網對通信網絡傳輸帶寬的需求達到了前所未有的高度,進而推動了光通信行業的再一次興盛。站在行業的高度來看,寬帶接入網無疑是推動行業發展的最主要領域。而實現寬帶接入網的最主要技術則是無源光網絡技術。無源光網絡的本質是一個樹型拓撲的光網絡,其主要的傳輸光纖可被多用戶共享,且在中央基站和用戶之間無任何有源器件,從而大大降低了網絡的成本。然而,在具體實踐中,仍然有許多的技術難題需要解決,例如:無色光網絡單元、突發性傳輸、全雙工傳輸、長距離無源光網絡和網絡功能集成等。這些技術需求亦反應了市場對通信技術發展的要求,及“更快,更便宜,更灵活“。 / 為滿足無源光網絡的技術要求,研究者們從不同的角度提出了各種解決方案,研究領域囊括光傳輸技術、新型器件、系統結構、網絡協議等等。本論文研究從傳輸碼型的角度來解決上述一項或幾項問題。研究碼型包括雙二進制反歸零碼,雙二進制曼切斯特碼,還有常規曼切斯特碼。研究內容則包括上述碼型的產生、接收、傳輸特性和系統應用等等。論文首貳章為概要和背景技術介紹,其餘幾章則按照不同的碼型分類討論。 / 本論文第一項研究課題為雙二進制反歸零碼。相比傳統的歸零碼和反歸零碼,雙二進制反歸零碼具有更大的色散容限,且每個傳輸符號均有能量。我們先研究了它的優勢,調製/解調方法,而後研究了該碼型在無源光網絡中的具體應用,包括10‐Gb/s 全光組播系統和基於重調製的80 公里長距離波分複用無源光網絡系統。 / 第二項研究課題為雙二進制曼切斯特碼型,該碼型的優勢包括較大的時鐘分量,窄帶寬,無直流分量等。我們提出了一種基於直接調製的雙二進制曼切斯特碼產生方法。該方法具有高效,低價,高輸出功率等特點。基於該雙二進制曼切斯特碼發射機,我們實現了70 公里雙向傳輸的波分複用無源光網絡。該系統下行傳輸採用雙二進制曼切斯特碼型,上行傳輸採用直接調製的反射式半導體激光器,所以系統成本大大降低。 / 最後,我們研究了電色散補償技術對於傳統曼切斯特碼型的傳輸性能的改善。所使用的電均衡技術包括前向均衡器、判決反饋均衡器和極大似然估計均衡器。通過離線處理的方法,我們對曼切斯特碼型在三種均衡器下的傳輸性能進行了實驗驗證。研究內容包括前向均衡器和判決反饋均衡器抽頭數的優化、不同採樣率下系統性能、極大似然估計中狀態機個數的影響和不同的曼切斯特接收機的影響等等。 / The increasing demands for bandwidth have aroused a myriad of industry and academic activities in developing high-speed and cost-effective optical networks,among which optical broad band access networks was the main driving force for such growth in recent years. The most promising solution to optical broadband access network is the passive optical network (PON), which is a point-to-multipoint tree-topology network that connects optical line terminal (OLT) with many optical network units (ONUs) via a long fiber feeder and many short distribution fibers. Promising the concept it is, it raises many detailed technical challenges, such as colorless ONUs, burst mode transmission, bi-directional transmission with mitigated backscattering noise, long-reach PON, and integrating network functionalities. All of the technical requirements are motivated by the “original requirements“ of telecommunication -- faster, cheaper, and more robust. / To fulfill the technical requirements, different researchers take different angles to design system and to study the enabling technologies. For example, devices, system architectures, network protocols, etc. In this thesis research, we have tried to deal with one or multiple problems by employing advanced modulation formats for the optical signals. In particular, we have studied IRZ-duobinary, Manchester-duobinary, and Manchester formats, including the modulation/demodulation techniques, transmission properties, and system applications. The research topics are classified according to the type of modulation formats. / In the first topic, IRZ-duobinary format is proposed for optical signal transmission. It has desirable properties of large dispersion tolerance (as compared to conventional RZ/IRZ) and finite optical power in each bit. In this study, we firstly show the advantages of IRZ-duobinary and the corresponding modulation techniques. Then, we demonstrate a 10-Gb/s per channel optical multicast overlay scheme and an 80-km-reach system with re-modulated ONU, both in wavelength division multiplexing (WDM) PON. / In the second topic, Manchester-duobinary format, which has the advantages including easy clock/level recovery, compressed bandwidth, and zero DC component, is studied. We propose an efficient and cost-effective Manchester-duobinary transmitter by properly modulating a chirp managed laser (CML) with electrical Manchester signal. Then, a cost-effective CLS 70-km-Reach full-duplex WDM-PON with downstream 10-Gb/s Manchester-duobinary signal and upstream 1.25-Gb/s re-modulated NRZ-OOK signal is proposed and experimentally demonstrated. This design simultaneously solves the problems of colorless ONU, bi-directional transmission, and long-reach, using cost-effective system design and devices. / Finally, we investigate the performance of electronic dispersion compensation (EDC) technique on 10-Gb/s Manchester coded optical signal, so as to further improve its dispersion tolerance and may enables its applications in long-reach PON. In this study, feed forward equalizer (FFE), decision feedback equalizer (DFE), and maximum-likelihood sequence estimation (MLSE) are employed as the equalizers Utilizing off-line signal processing, the performance of different equalizers with different parameters (number of taps, sampling rates, number of states, etc.) under both cases of single-ended and balanced detection are studied and compared. Experimental results show that the transmission distance of Manchester coded signal can be increased by a factor of three with four-sample-per-symbol FFE-DFE. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Liu, Zhixin. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 128-148). / Abstract also in Chinese. / Acknowledgement --- p.1 / Abstract --- p.3 / 摘要 --- p.5 / Table of contents --- p.7 / List of figures and tables --- p.13 / Chapter Chapter 1. --- Introduction / Chapter 1.1 --- Optical Broadband Access --- p.18 / Chapter 1.1.1 --- Bandwidth requirement --- p.19 / Chapter 1.1.2 --- Passive optical networks --- p.22 / Chapter 1.2 --- Research Challenge of Next-Generation Optical Access Network --- p.25 / Chapter 1.2.1 --- Colorless ONU --- p.25 / Chapter 1.2.2 --- Burst Mode Transmission --- p.27 / Chapter 1.2.3 --- Backscattering Noise in PON --- p.28 / Chapter 1.2.4 --- Long-Reach Access Network --- p.30 / Chapter 1.2.5 --- Enriching Network Functionalities --- p.31 / Chapter 1.3 --- Major contribution of this thesis --- p.32 / Chapter 1.3.1 --- IRZ-duobinary transmitter and application --- p.32 / Chapter 1.3.2 --- Manchester-duobinary transmitter and application --- p.33 / Chapter 1.3.3 --- Receiver with electronic equalizer for Manchester signal --- p.34 / Chapter 1.4 --- Outline of this Thesis --- p.35 / Chapter Chapter 2. --- Optical Modulation Technique and Transmission Impairments / Chapter 2.1 --- Optical Modulation techniques --- p.38 / Chapter 2.1.1 --- Chirp managed laser --- p.38 / Chapter 2.1.2 --- Mach-Zehnder modulator --- p.41 / Chapter 2.2 --- Transmission Impairments --- p.47 / Chapter 2.2.1 --- Noise --- p.47 / Chapter 2.2.2 --- Chromatic dispersion --- p.49 / Chapter 2.2.3 --- Fiber nonlinearity --- p.50 / Chapter 2.3 --- Impairment Mitigation Techniques --- p.51 / Chapter 2.3.1 --- In-line compensation techniques --- p.51 / Chapter 2.3.2 --- Post-compensation techniques --- p.52 / Chapter Chapter 3. --- Optical Multicast and Re-modulation Based on Inverse-RZ-duobinary Transmitter / Chapter 3.1 --- Introduction --- p.53 / Chapter 3.2 --- IRZ-duobinary transmitter --- p.55 / Chapter 3.2.1 --- Generation of IRZ-duobinary format --- p.55 / Chapter 3.2.2 --- Comparison of different configurations of IRZ-duobinary generation --- p.56 / Chapter 3.3 --- IRZ-duobinary format for optical multicast in WDM-PON --- p.60 / Chapter 3.3.1 --- Optical multicast in WDM-PON --- p.60 / Chapter 3.3.2 --- Proposed system architecture --- p.61 / Chapter 3.3.3 --- Experimental demonstration of the proposed optical multicast system --- p.65 / Chapter 3.4 --- IRZ-duobinary for long-reach PON --- p.68 / Chapter 3.4.1 --- Long-reach PON using DI based IRZ-duobinary transmitter --- p.69 / Chapter 3.4.2 --- Long-reach PON using CML based IRZ-duobinary transmitter --- p.75 / Chapter 3.5 --- Summary --- p.81 / Chapter Chapter 4. --- Manchester-duobinary Transmitter for Bi-directional WDM-PON / Chapter 4.1 --- Introduction --- p.83 / Chapter 4.2 --- Manchester-duobinary transmitter --- p.85 / Chapter 4.2.1 --- Mach-Zehnder modulator based Manchester-duobinary transmitter --- p.85 / Chapter 4.2.2 --- Chirp managed laser based Manchester-duobinary transmitter --- p.87 / Chapter 4.3 --- Rayleigh noise mitigated bi-directional WDM-PON based on Manchester-duobinary transmitter --- p.94 / Chapter 4.3.1 --- CLS Bi-directional long-reach WDM-PON. --- p.94 / Chapter 4.3.2 --- Proposed system architecture --- p.97 / Chapter 4.3.3 --- Experimental demonstration --- p.99 / Chapter 4.4 --- Summary --- p.102 / Chapter Chapter 5. --- Electronic Equalizer for Manchester Coded Signal / Chapter 5.1 --- Introduction --- p.103 / Chapter 5.2 --- Electronic equalizer for CD compensation --- p.104 / Chapter 5.2.1 --- Channel model --- p.104 / Chapter 5.2.2 --- FFE-DFE --- p.106 / Chapter 5.2.3 --- MLSE --- p.107 / Chapter 5.3 --- FFE-DFE for Manchester signal --- p.109 / Chapter 5.3.1 --- Experimental setup for CD compensation of Manchester signal using FFE-DFE --- p.110 / Chapter 5.3.2 --- Results and discussion --- p.112 / Chapter 5.4 --- MLSE equalizer for Manchester signal --- p.121 / Chapter 5.4.1 --- Experimental setup for CD compensation of Manchester format using MLSE --- p.121 / Chapter 5.4.1 --- Results and discussion --- p.122 / Chapter 5.5 --- Summary --- p.124 / Chapter Chapter 6. --- Conclusion / Chapter 6.1 --- Summary of this thesis --- p.125 / Chapter 6.2 --- Future work --- p.127 / References --- p.128 / Chapter Appendix: --- p.149 / Chapter A. --- List of abbreviations --- p.149 / Chapter B. --- List of publications --- p.154
3

All-optical signal processing based on optical parametric amplification

Lai, Ming-fai, 黎明輝 January 2008 (has links)
published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy
4

High speed all-optical wavelength conversion

Stephens, Marc Francis Charles January 1998 (has links)
No description available.
5

Active optical switching and waveguiding in injection lasers

MacLean, D. January 1986 (has links)
No description available.
6

Computation of wave propagation in integrated optical devices

Koch, Thomas Bertold January 1989 (has links)
No description available.
7

Optical filter design for SCM demultiplexing

Rojas, Luis Eduardo Gomez January 1995 (has links)
No description available.
8

Design considerations for an optical PSK homodyne receiver

Grant, Michael Alistair January 1986 (has links)
No description available.
9

Fourier methods for the analysis of integrated optics devices

Smartt, Christopher James January 1995 (has links)
No description available.
10

Vertical grating assisted coupling between waveguide layers

Chan, Gordon Siu Fan January 1995 (has links)
No description available.

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