Perfomance evaluation of maximum likelihood sequence estimation receivers in lightwave systems with optical amplifiers

Maximum likelihood sequence estimation (MLSE) has been proposed in earlier literature to combat the e®ects of nonlinear dispersion in intensity modulation/direct detection (IM/DD) optical channels. In this paper, we develop a theory of the bit error rate (BER) of MLSE-based IM/DD receivers operating in the presence of nonlinear dispersion and amplified spontaneous emission (ASE) noise. We focus on long haul or metro links spanning several hundred kilometers of single model fibers with optical amplifiers. Numerical results show a close agreement between the predictions of the theory and computer simulations.Fil: Crivelli, Diego Ernesto. Universidad Nacional de Córdoba. Facultad de Cs.exactas Físicas y Naturales. Departamento de Electronica. Laboratorio de Comunicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Carrer, Hugo Santiago. Universidad Nacional de Córdoba. Facultad de Cs.exactas Físicas y Naturales. Departamento de Electronica. Laboratorio de Comunicaciones; ArgentinaFil: Hueda, Mario Rafael. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Estudios Avanzados en Ingeniería y Tecnología. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Estudios Avanzados en Ingeniería y Tecnología; Argentin

Reduced complexity maximum likelihood sequence estimator for high-speed fiber optic communication systems

In this paper we present a new reduced complexity maximum likelihood sequence detector for intensity modulation / direct detection (IM/DD) fiber optic systems. The proposed detector takes into account the presence of thermal and amplified spontaneous emission (ASE) noise. The results presented here show a negligible performance degradation from the optimum receiver, while implementation complexity is significantly reduced. The mathematical models derived in this paper are attractive for the design and analysis of very high speed optical receivers.    Fil: Carrer, Hugo Santiago. Universidad Nacional de Córdoba. Facultad de Cs.exactas Físicas y Naturales. Departamento de Electronica. Laboratorio de Comunicaciones; ArgentinaFil: Crivelli, Diego Ernesto. Universidad Nacional de Córdoba. Facultad de Cs.exactas Físicas y Naturales. Departamento de Electronica. Laboratorio de Comunicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Hueda, Mario Rafael. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Estudios Avanzados en Ingeniería y Tecnología. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Estudios Avanzados en Ingeniería y Tecnología; Argentin

Demonstration of 10 Gbit/s transmission over 900 km SMF with <400 ns adaptation time using full-field EDC

This reported work significantly extends the reach of 10Gbit/s on-off keying singlemode fibre (SMF) transmission using full-field based electronic dispersion compensation (EDC) to 900 km. In addition, the EDC balances the complexity and the adaptation capability by employing a simple dispersive transmission line with static parameters for coarse dispersion compensation and 16-state maximum likelihood sequence estimation with Gaussian approximation based channel training for adaptive impairment trimming. Improved adaptation times of less than 400 ns for a bit error rate target of 10-3 over distances ranging from 0 to 900 km are reported

Chromatic dispersion compensation using full-field maximum-likelihood sequence estimation

We investigate full-field detection-based maximum-likelihood sequence estimation (MLSE) for chromatic dispersion compensation in 10 Gbit/s OOK optical communication systems. Important design criteria are identified to optimize the system performance. It is confirmed that approximately 50% improvement in transmission reach can be achieved compared to conventional direct-detection MLSE at both 4 and 16 states. It is also shown that full-field MLSE is more robust to the noise and the associated noise amplifications in full-field reconstruction, and consequently exhibits better tolerance to nonoptimized system parameters than full-field feedforward equalizer. Experiments over 124 km spans of field-installed single-mode fiber without optical dispersion compensation using full-field MLSE verify the theoretically predicted performance benefits

Applications of Kalman Filters for Coherent Optical Communication Systems

In this chapter, we review various applications of Kalman filtering for coherent optical communication systems. First, we briefly discuss the principles of Kalman filter and its variations including extended Kalman filter (EKF) and adaptive Kalman filter (AKF). Later on, we illustrate the applicability of Kalman filters for joint tracking of several optical transmission impairments, simultaneously, by formulating the state space model (SSM) and detailing the principles. A detailed methodology is presented for the joint tracking of linear and nonlinear phase noise along with amplitude noise using EKF. Also, approaches to enhance the performance obtained by EKF by combining with other existing digital signal processing (DSP) techniques are presented. Frequency and phase offset estimation using a two stage linear Kalman filter (LKF)/EKF is also discussed. A cascaded structure of LKF and EKF by splitting the SSM to jointly mitigate the effects of polarization, phase and amplitude noise is also presented. The numerical analysis concludes that the Kalman filter based approaches outperform the conventional methods with better tracking capability and faster convergence besides offering more feasibility for real-time implementations

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

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.1Abstract --- p.3摘要 --- p.5Table of contents --- p.7List of figures and tables --- p.13Chapter Chapter 1. --- IntroductionChapter 1.1 --- Optical Broadband Access --- p.18Chapter 1.1.1 --- Bandwidth requirement --- p.19Chapter 1.1.2 --- Passive optical networks --- p.22Chapter 1.2 --- Research Challenge of Next-Generation Optical Access Network --- p.25Chapter 1.2.1 --- Colorless ONU --- p.25Chapter 1.2.2 --- Burst Mode Transmission --- p.27Chapter 1.2.3 --- Backscattering Noise in PON --- p.28Chapter 1.2.4 --- Long-Reach Access Network --- p.30Chapter 1.2.5 --- Enriching Network Functionalities --- p.31Chapter 1.3 --- Major contribution of this thesis --- p.32Chapter 1.3.1 --- IRZ-duobinary transmitter and application --- p.32Chapter 1.3.2 --- Manchester-duobinary transmitter and application --- p.33Chapter 1.3.3 --- Receiver with electronic equalizer for Manchester signal --- p.34Chapter 1.4 --- Outline of this Thesis --- p.35Chapter Chapter 2. --- Optical Modulation Technique and Transmission ImpairmentsChapter 2.1 --- Optical Modulation techniques --- p.38Chapter 2.1.1 --- Chirp managed laser --- p.38Chapter 2.1.2 --- Mach-Zehnder modulator --- p.41Chapter 2.2 --- Transmission Impairments --- p.47Chapter 2.2.1 --- Noise --- p.47Chapter 2.2.2 --- Chromatic dispersion --- p.49Chapter 2.2.3 --- Fiber nonlinearity --- p.50Chapter 2.3 --- Impairment Mitigation Techniques --- p.51Chapter 2.3.1 --- In-line compensation techniques --- p.51Chapter 2.3.2 --- Post-compensation techniques --- p.52Chapter Chapter 3. --- Optical Multicast and Re-modulation Based on Inverse-RZ-duobinary TransmitterChapter 3.1 --- Introduction --- p.53Chapter 3.2 --- IRZ-duobinary transmitter --- p.55Chapter 3.2.1 --- Generation of IRZ-duobinary format --- p.55Chapter 3.2.2 --- Comparison of different configurations of IRZ-duobinary generation --- p.56Chapter 3.3 --- IRZ-duobinary format for optical multicast in WDM-PON --- p.60Chapter 3.3.1 --- Optical multicast in WDM-PON --- p.60Chapter 3.3.2 --- Proposed system architecture --- p.61Chapter 3.3.3 --- Experimental demonstration of the proposed optical multicast system --- p.65Chapter 3.4 --- IRZ-duobinary for long-reach PON --- p.68Chapter 3.4.1 --- Long-reach PON using DI based IRZ-duobinary transmitter --- p.69Chapter 3.4.2 --- Long-reach PON using CML based IRZ-duobinary transmitter --- p.75Chapter 3.5 --- Summary --- p.81Chapter Chapter 4. --- Manchester-duobinary Transmitter for Bi-directional WDM-PONChapter 4.1 --- Introduction --- p.83Chapter 4.2 --- Manchester-duobinary transmitter --- p.85Chapter 4.2.1 --- Mach-Zehnder modulator based Manchester-duobinary transmitter --- p.85Chapter 4.2.2 --- Chirp managed laser based Manchester-duobinary transmitter --- p.87Chapter 4.3 --- Rayleigh noise mitigated bi-directional WDM-PON based on Manchester-duobinary transmitter --- p.94Chapter 4.3.1 --- CLS Bi-directional long-reach WDM-PON. --- p.94Chapter 4.3.2 --- Proposed system architecture --- p.97Chapter 4.3.3 --- Experimental demonstration --- p.99Chapter 4.4 --- Summary --- p.102Chapter Chapter 5. --- Electronic Equalizer for Manchester Coded SignalChapter 5.1 --- Introduction --- p.103Chapter 5.2 --- Electronic equalizer for CD compensation --- p.104Chapter 5.2.1 --- Channel model --- p.104Chapter 5.2.2 --- FFE-DFE --- p.106Chapter 5.2.3 --- MLSE --- p.107Chapter 5.3 --- FFE-DFE for Manchester signal --- p.109Chapter 5.3.1 --- Experimental setup for CD compensation of Manchester signal using FFE-DFE --- p.110Chapter 5.3.2 --- Results and discussion --- p.112Chapter 5.4 --- MLSE equalizer for Manchester signal --- p.121Chapter 5.4.1 --- Experimental setup for CD compensation of Manchester format using MLSE --- p.121Chapter 5.4.1 --- Results and discussion --- p.122Chapter 5.5 --- Summary --- p.124Chapter Chapter 6. --- ConclusionChapter 6.1 --- Summary of this thesis --- p.125Chapter 6.2 --- Future work --- p.127References --- p.128Chapter Appendix: --- p.149Chapter A. --- List of abbreviations --- p.149Chapter B. --- List of publications --- p.15