Digital Coherent Optical Systems

Digital Coherent Optical Systems

Author: Darli Augusto de Arruda Mello

Publisher: Springer Nature

Published: 2021-03-08

Total Pages: 238

ISBN-13: 3030665410

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This textbook details the architecture of a digital coherent optical system and describes its main digital signal processing (DSP) algorithms. The authors first show how the combination of advanced modulation techniques, DSP and coherent detection has led to significant gains in capacity and ease of operation. The authors follow the path of the information from its generation in the transmitter, to propagation through the fiber and processing by the DSP algorithms in the receiver. The work summarizes academic results and presents them in a didactic way to students and practitioners working on the area of optical communications. A full suite of classroom materials is included for easy integration into a curriculum, containing theoretic and simulation problems, and off-the-shelf Matlab/Octave functions.


Reconfigurable Technology for Future Optical Access Networks

Reconfigurable Technology for Future Optical Access Networks

Author: She-Hwa Yen

Publisher: Stanford University

Published: 2011

Total Pages: 145

ISBN-13:

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Fiber-based access is recognized as the most promising technology for solving broadband bandwidth bottlenecks. Time division multiplexing passive optical networks (TDM-PONs) that are passive and non-reconfigurable are currently the most widely deployed type of fiber access networks. However, due to their passive nature, TDM-PONs faces several limitations such as inflexible service area coverage, lack of intelligence for control, and inability to counteract security attacks. In order to address the current limitations of optical access networks, we propose reconfigurable technologies for next generation PONs. Two novel reconfigurable technologies are proposed, analyzed, and experimentally evaluated. The first solution is a reconfigurable power-and wavelength- assignment technology based on a novel non-volatile, reconfiguration node. The proposed remote node can reconfigure the network to adapt it to varying degrees of deployment conditions and/or network attacks. Moreover, the proposed remote node incorporates a novel quasi-passive device that does not consume energy once it is reconfigured into a new latching state. Therefore, the proposed remote node has very low energy consumption and does not require local power supply to preserve the passive character of the distribution network. In particular, two novel quasi-passive optical power splitter technologies based on Micro-Electro-Mechanical Systems (MEMS) and transition metal oxide have been designed for the reconfigurable device. A simulation study shows the proposed reconfigurable device would outperform traditional passive splitter in terms of maximum number of supportable users under realistic deployment conditions. The second solution addresses the issue of reconfigurable network consolidation and infrastructure simplification. Current TDM-PONs suffers from limited reach and split-ratio. To enhance the performance in terms of service range and quality of service, reconfigurable network consolidation is a promising solution. It can also simplify the network and reduce cost. We propose the following novel reconfigurable technologies for consolidation and simplification of next generation access networks: (1) Passive reach-extension technology for the drop section of optical access networks; (2) Sleep mode ONUs for energy saving; (3) Centrally managed optical signature that can monitor and protect the upstream link; and (4) Multi-rate burst mode receivers. These reconfigurable technologies can bring the intelligence into optical access networks and improve the efficiency and flexibility for next generation optical access networks.


Coherent Optics for Access Networks

Coherent Optics for Access Networks

Author: Zhensheng Jia

Publisher: CRC Press

Published: 2019-10-28

Total Pages: 128

ISBN-13: 1000736962

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This book will highlight the motivation for coherent optics in access and introduce digital coherent optical system in detail, including advanced modulation formats, architecture of modulation and detection, and DSP flow for both transmitter and receiver. This book will also demonstrate potential approaches to re-design and re-engineer the digital coherent concept from long-haul and metro solutions to the access network, leveraging reduction in complexity and cost as well as the benefits of capacity increases and operational improvements. This book will illustrate the details on optimization of the digital, optical, and electrical complexity and standardization and interoperability.


Real-time Digital Signal Processing for New Wavelength-to-the-user Optical Access Networks

Real-time Digital Signal Processing for New Wavelength-to-the-user Optical Access Networks

Author: Saeed Ghasemi

Publisher:

Published: 2020

Total Pages: 135

ISBN-13:

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Nowadays, optical access networks provide high capacity to end users with growing availability of multimedia contents that can be streamed to fixed or mobile devices. In this regard, one of the most flexible and low-cost approaches is Passive Optical Network (PON) that is used in Fiber-to-the-Home (FTTH). Due to the growing of the bandwidth demands, Wavelength Division Multiplexing (WDM), and later on ultra-dense WDM (udWDM) PON, with a narrow channel spacing, to increase the number of users through a single fiber, has been deployed.The udWDM-PON with coherent technology is an attractive solution for the next generation optical access networks with advanced digital signal processing (DSP). Thanks to the higher sensitivity and improved channel selectivity in coherent detection with efficient DSP, optical networks support larger number of users in longer distances.Since the cost is the main concern in the optical access networks, this thesis presents DSP architectures in coherent receiver (Rx), based on low-cost direct phase modulated commercial DFB lasers. The proposals are completely in agreement with consept of wavelength-to-the-user, where each client in optical network is dedicated to an individual wavelength. Next, in a 6.25 GHz spaced udWDM grid with the optimized DSP techniques and phase-shift-keying (PSK) modulation format, the high sensitivity is achieved in real-time field-programmable-gate-array (FPGA) implementations. Moreover, this thesis reduces hardware complexity of optical carrier recovery (CR) with two various strategies. First, based on differential mth-power frequency estimator (FE) by using look-up-tables (LUTs) and second, LUT-free CR architecture, with optimizing the power consumption and hardware resources, as well as improving the channel selectivity in terms of speed and robustness.Furthermore, by designing very simple but efficient clock recovery, a symbol-rate DSP architecture, which process data using only one sample per symbol (1-sps), for polarization diversity (POD) structure, becomes possible. It makes the DSP independent from state-of-polarization (SOP), even in the case of low-cost optical front-end and low-speed analog-to-digital converters (ADCs), keeps the performance high as well as sensitivity in real-time implementations on FPGA.


UltraFlow Dual-mode Access Network

UltraFlow Dual-mode Access Network

Author: Shuang Yin

Publisher:

Published: 2016

Total Pages:

ISBN-13:

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Optical Flow Switching (OFS) network has been proposed as a complement to the existing Electronic Packet Switching (EPS) based network for its high efficiency in transmitting large files. UltraFlow access network enables OFS in the access network domain, and provides dual-mode services to the end users, i.e., conventional IP and novel Flow. The UltraFlow dual-mode network architecture is a promising solution to the problem of ever-increasing growth of Internet traffic and the newly emerging network applications. The UltraFlow project involves the collaboration of three universities: Stanford University, Massachusetts Institute of Technology (MIT), and University of Texas at Dallas. The MIT group focuses on the design and analysis of OFS in the core and metro network, while the focus of UT Dallas is on designing and analyzing the UltraFlow control plane. At Stanford University, we focus on designing and experimentally demonstrating the UltraFlow dual-mode access network. This dissertation proposes and discusses the concept, architecture, design, implementation and potential applications of the UltraFlow dual-mode access network. The rest of this dissertation is organized as follows. First, this dissertation introduces the concept the UltraFlow dual-mode access network and shows that this architecture is crucial to achieve high throughput transmission considering various Internet traffic patterns. Also presented is the physical layer implementation of UltraFlow dual-mode access network, which coexists with the legacy Passive Optical Networks (PONs). The transport layer design and software defined control plane will also be briefly described. This dissertation next discusses a novel Intra-PON Flow communication architecture, which enables transparent lightpaths among users located in the same access network. Intra-PON channels can support advanced network applications, e.g., video/file server backup, and Coordinated Multipoint (CoMP) transmission in the 5G mobile network era. The proposed architecture adopts a Quasi-PAssive Reconfigurable (QPAR) node, proposed and developed by our group previously, in the UltraFlow access network testbed, which enables dynamic wavelength allocation and improves the UltraFlow dual-mode access network performance. Experimental results then appear on remotely pumped Erbium Doped Fiber Amplifier (EDFA) and distantly powered QPAR node, which can maintain the passive nature of the legacy PONs and achieve high split ratio. This work also investigates and assesses the network performance advantages of Intra-PON Flow transmission via extensive network simulations. Finally, the dissertation reports the line rate evolution paths, beyond state-of-the-art 10 Gbps per wavelength transmission, for the next generation optical access network. This report shows the feasibility of implementing low-cost 25 and 40 Gbps per wavelength transmission in PONs. Advance modulation formats, i.e., Electrical Duobinary (EDB) and 4-level Pulse Amplitude Modulation (PAM-4), optical amplification, and Digital Signal Processing (DSP) are considered as key technologies to support the data rate increase and maintain relatively low system cost with 10 Gbps grade optics. This work includes the experimental results on system power budget, split ratio, and reach for both 25 and 40 Gbps per wavelength transmission with different system designs, and suggests an optimal set of system specifications for both 25 and 40 Gbps transmission.


Springer Handbook of Optical Networks

Springer Handbook of Optical Networks

Author: Biswanath Mukherjee

Publisher: Springer Nature

Published: 2020-10-15

Total Pages: 1169

ISBN-13: 3030162508

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This handbook is an authoritative, comprehensive reference on optical networks, the backbone of today’s communication and information society. The book reviews the many underlying technologies that enable the global optical communications infrastructure, but also explains current research trends targeted towards continued capacity scaling and enhanced networking flexibility in support of an unabated traffic growth fueled by ever-emerging new applications. The book is divided into four parts: Optical Subsystems for Transmission and Switching, Core Networks, Datacenter and Super-Computer Networking, and Optical Access and Wireless Networks. Each chapter is written by world-renown experts that represent academia, industry, and international government and regulatory agencies. Every chapter provides a complete picture of its field, from entry-level information to a snapshot of the respective state-of-the-art technologies to emerging research trends, providing something useful for the novice who wants to get familiar with the field to the expert who wants to get a concise view of future trends.


Optical Switching

Optical Switching

Author: Tarek S. El-Bawab

Publisher: Springer Science & Business Media

Published: 2008-02-11

Total Pages: 458

ISBN-13: 0387291598

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Applications of optical switching in network elements and communication networks are discussed in considerable depth. Optical circuits, packet, and burst switching are all included. Composed of distinct self-contained chapters with minimum overlaps and independent references. Provides up-to-date comprehensive coverage of optical switching, technologies, devices, systems and networks. Discusses applications of optical switching in network elements and communications networks.