A model is developed for the optimization. The model can be used for the merger of both identical and non-identical networks. The overall costs for various topologies are optimized with respect to different interconnection build costs. It is shown that the merger of two optical networks can reduce more than 50% of operational fiber links, while routing between any two nodes in the two optical networks are maintained. This has been proven through case analysis and analytical results. / An algorithm for resource optimization is also developed for the consolidation of two coexisting networks. In all cases after critical interconnection build cost, only two interconnection fiber links are needed. It is shown that the optimization is to find a Hamiltonian path that covers all the nodes in each network or to find a path that contains a maximum number of directly connected articulation nodes with different groupings. / Case analysis results for part of a real China network and other topologies are discussed. Analytical results can be derived for both the minimum number of links required for arbitrary connected networks and the locations of the two interconnections for the merger of two networks. In addition, more comprehensive analysis on the effects of node degree, protection, and traffic demand are discussed. It is conclusive that through the merger of two optical networks substantial saving to the network operator will occur. / In this thesis, the merger of two networks by adding interconnection fiber links is investigated. Interconnection fiber links are only allowed at the co-located nodes of the two networks. With the additional interconnection links, it is possible to reduce the number of fiber links that are operational while maintaining the full connectivity between any two nodes in the two networks. By suspending some of the fiber links, the operational expenses of those links can be saved. Optimal cost and the number of interconnection links with their optimal locations for the merger of the two optical networks are investigated. / Telecommunication networks have been designed to carry voice traffic for decades. With the growth of data traffic in recent years, network operators have constructed substantial amount of fiber optic networks. Multiple telecommunication networks create redundancy in fiber resources. Resources have not been used optimally and revenue has plunged to its lowest since inception. Many network operators are considering co-location and merging in order to reduce cost. Merging two networks can achieve operational savings in redundant fiber links and therefore cost saving to the network operator. / The proposed model finds the optimal interconnection locations for different topologies. We analyzed the optimal location for several cases when the number of interconnection fiber links is two and some analytical results are derived. This assists network planners to focus on the optimal locations for interconnection links to be installed. / Leung, Raymond Hai Ming. / Adviser: Lian Kuan Chen. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3690. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 112-115). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

At present, optical fiber transmissions are dominated by intensity modulation and direct detection, which fundamentally limit the signal processing capabilities in optical fiber networks. On the other hand, manipulation of optical phase enables advanced signal processing techniques for various applications. This thesis includes three parts and makes contributions in three research areas in optical fiber networks, by applying optical and electronic signal processing techniques. In the first part of the thesis, optical signal processing is employed to realize a novel all-optical label swapping (AOLS) technique using synchronous phase modulation. This technique is shown to address the forwarding speed bottleneck in optical packet switched networks (OPSN). By exploiting the unique symmetry of phase-shift keying (PSK), for the first time, label erasure and insertion are performed in a single step by a phase modulator without wavelength conversion. We also propose and demonstrate a polarization insensitive phase modulator to address the polarization sensitivity of AOLS. Furthermore, we emulate multi-hop all-optical label swapping in a re-circulating loop to investigate the power penalties from the accumulated phase errors and the timing mismatch. Based on the experimental and analytical results, we show that this technique can save wavelength converters significantly if compared with conventional AOLS techniques requiring dedicate wavelength converters.

Analogcircuit/IC design for high speed optical fiber communication is a fairly new research area in Dr. Ha's group. In the first project sponsored by ETRI (Electronics and Telecommunication Research Institute) we started to design the building blocks of receiver for next generation 400 Gb/s optical fiber communication. In this thesis research a transceiver architecture based on 4x100 Gb/s parallel communication is proposed. As part of the receiver, a transimpedance amplifier for 100 Gb/s optical communication is designed, analyzed and simulated. Simulation results demonstrate the excellent feasibility of proposed architecture. Bipolar technology based on III-V materials (e.g. - GaAs, InP based HBT, HEMT) has always dominated the high speed optical transceiver design because of their inherent properties of high mobility and low noise. But they are power hungry and bulky in size which made them less attractive for highly integrated circuit design. On the contrary, CMOS technology always drew attraction because of low cost, low power dissipation and high level of integration facility. But their notorious parasitic characteristic and inferior noise performance makes high speed transceiver design very challenging. The emergence of nano-scale CMOS offer highly scaled feature sized transistors with transition frequencies exceeding 200 GHz and can improve optical receiver performance significantly. Increasing bandwidth to meet the target data rate is the most challenging task of TIA design especially in CMOS technology. Several CMOS TIA architectures have been published recently [6]-[11] for 40 Gb/s data rate having bandwidth no more than 40 GHz. In contrast to existing works, the goal of this research is to step further and design a single channel stand-alone TIA compatible in serial 100 Gb/s data rate with enhanced bandwidth and optimized transimpedance gain, input referred noise and group delay variation. A 100 Gb/s transimpedance amplifier (TIA) for optical receiver front end is designed in this work. To achieve wide bandwidth and low group delay variation a differential TIA with active feedback network is proposed. Proposed design also combines regulated cascode front end, peaking inductors and capacitive degeneration to have wide band response. Simulation results show 70 GHz bandwidth, 42 dBΩ transimpedance gain and 2.8 ps of group delay variation for proposed architecture. Input referred noise current density is 26 pA/â while the total power dissipation from 1.2V supply is 24mW. Performance of the proposed TIA is compared with other existing TIAs, and the proposed TIA shows significant improvement in bandwidth and group delay variation compared to other existing TIA architectures. / Master of Science

Both gain transient and dynamic gain control devices were also designed and fabricated as photonic integrated circuits (PICs). Silicon-based PICs were able to perform dynamic gain tilt compensation by thermo-optic effect. Helium doped SOI rib waveguides were used for power monitoring and is potentially used as monolithic gain tilt compensation device with arrayed waveguide grating (AWG). / Dynamic gain tilt induced by wavelength dependent gain of EDFA leads to power penalty in wavelength division multiplexed systems. Using optical filter with known spectral response, it is possible to detect dynamic gain tilt and a per-band compensation scheme using electronic variable optical attenuators. This was implemented for dynamic gain tilt compensation (DGTC). / Dynamic provisioning of bandwidth and re-configurable optical networks can potentially allow efficient and cost effective deliveries of services based on the actual bandwidth requirement. Optical add/drop multiplexers (OADM) and optical cross-connects (OXC) will be used for such networks but the dynamic provisioning of optical channels may introduce optical power transients because of the slow gain dynamics of erbium doped fiber amplifiers. In this dissertation, the potential problems on using Erbium Doped Fiber Amplifiers (EDFA) in future reconfigurable optical networks are studied and possible solutions are assessed. In particular, the problems of gain transient and dynamic gain tilt were studied experimentally and theoretically. / In saturated EDFA channel add/drop can produce average power fluctuations, in timescales in the microsecond range. The thesis describes how gain transients can be minimized in gain clamped EDFA by optimizing erbium concentrations of EDF. Both simulations and experiments demonstrate that highly doped EDF minimize the transient in gain clamped EDFA. For unclamped EDFA, all-optical feedforward constant output power compensation has been successfully demonstrated using electronic variable optical attenuator (EVOA). / Chan Po Shan. / "August 2006." / Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1813. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Chong, Kin Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (p. 58-63). / Abstract also in Chinese. / Acknowledgement --- p.i / Abstract --- p.ii / 摘要 --- p.iv / Table of contents --- p.vi / List of figures and tables --- p.viii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1. --- Overview of optical regeneration --- p.1 / Chapter 1.1.1. --- O-E-O regeneration --- p.3 / Chapter 1.1.2. --- All-optical regeneration --- p.5 / Chapter 1.2. --- Motivation of this thesis --- p.7 / Chapter 1.3. --- Outline of this thesis --- p.9 / Chapter Chapter 2 --- Previous schemes of all-optical regeneration --- p.10 / Chapter 2.1. --- Introduction --- p.10 / Chapter 2.2. --- Fiber-based all-optical regeneration --- p.12 / Chapter 2.2.1. --- SPM-based regeneration --- p.12 / Chapter 2.2.2. --- FWM-based regeneration --- p.15 / Chapter 2.3. --- Semiconductor-based all-optical regeneration --- p.18 / Chapter 2.3.1. --- XGM-based regeneration --- p.18 / Chapter 2.3.2. --- XAM-based regeneration --- p.20 / Chapter 2.4. --- Multi-wavelength regeneration --- p.22 / Chapter 2.5. --- Summary --- p.23 / Chapter Chapter 3 --- Multi-wavelength optical 2R regeneration utilizing self-phase modulation and inter-channel walk-off control in fiber --- p.25 / Chapter 3.1. --- Introduction --- p.25 / Chapter 3.2. --- System architecture of the regenerator --- p.27 / Chapter 3.3. --- Experimental setup --- p.28 / Chapter 3.4. --- Results and discussions --- p.32 / Chapter 3.4.1. --- Effects of the improper inter-channel walk-off --- p.35 / Chapter 3.4.2. --- Effects of the improper filter offset --- p.36 / Chapter 3.5. --- Summary --- p.39 / Chapter Chapter 4 --- Investigation of the scalability and cascadability of our proposed multi-wavelength regeneration scheme --- p.40 / Chapter 4.1. --- Introduction --- p.40 / Chapter 4.2. --- Simulation models and results --- p.41 / Chapter 4.2.1. --- 10x10-Gb/s scenario --- p.41 / Chapter 4.2.2. --- 4x40-Gb/s scenario --- p.47 / Chapter 4.3. --- Discussions --- p.51 / Chapter 4.4. --- Summary --- p.53 / Chapter Chapter 5 --- Conclusion and future works --- p.54 / Chapter 5.1. --- Summary of the thesis --- p.54 / Chapter 5.2. --- Future works --- p.55 / List of publications --- p.57 / Bibliography --- p.58

Shen, Dong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (p. 98-106). / Abstracts in English and Chinese. / Abstract --- p.i / 摘要 --- p.iv / Acknowledgements --- p.v / Table of Contents --- p.vi / Chapter Chapter 1 --- Background --- p.1 / Chapter 1.1 --- Translucent Optical Networks --- p.1 / Chapter 1.1.1 --- The Way Towards Translucent --- p.1 / Chapter 1.1.2 --- Translucent Optical Network Architecture Design and Planning --- p.3 / Chapter 1.1.3 --- Other Research Topics in Translucent Optical Networks --- p.6 / Chapter 1.2 --- Fault Monitoring in All-Optical Networks --- p.12 / Chapter 1.2.1 --- Fault Monitoring in Network Layer's Perspective --- p.12 / Chapter 1.2.2 --- Passive Optical Monitoring --- p.14 / Chapter 1.2.3 --- Proactive Optical Monitoring --- p.16 / Chapter 1.3 --- Contributions --- p.17 / Chapter 1.3.1 --- Translucent Optical Network Planning with Heterogeneous Modulation Formats --- p.17 / Chapter 1.3.2 --- Multiplexing Optimization in Translucent Optical Networks --- p.19 / Chapter 1.3.3 --- An Efficient Regenerator Placement and Wavelength Assignment Scheme in Translucent Optical Networks --- p.20 / Chapter 1.3.4 --- Adaptive Fault Monitoring in All-Optical Networks Utilizing Real-Time Data Traffic --- p.20 / Chapter 1.4 --- Organization of Thesis --- p.22 / Chapter Chapter 2 --- Regenerator Placement and Resource Allocation Optimization in Translucent Optical Networks --- p.23 / Chapter 2.1 --- Introduction --- p.23 / Chapter 2.2 --- Translucent Optical Network Planning with Heterogeneous Modulation Formats --- p.25 / Chapter 2.2.1 --- Motivation and Problem Statements --- p.25 / Chapter 2.2.2 --- A Two-Step Planning Algorithm Using Two Modulation Formats to Realize Any-to-Any Topology Connectivity --- p.28 / Chapter 2.2.3 --- Illustrative Examples --- p.30 / Chapter 2.2.3 --- ILP Formulation of Minimizing Translucent Optical Network Cost with Two Modulation Formats under Static Traffic Demands --- p.34 / Chapter 2.2.4 --- Illustrative Numeric Examples --- p.42 / Chapter 2.3 --- Resource Allocation Optimization in Translucent Optical Networks --- p.45 / Chapter 2.3.1 --- Multiplexing Optimization with Auxiliary Graph --- p.45 / Chapter 2.3.2 --- Simulation Study of Proposed Algorithm --- p.51 / Chapter 2.3.3 --- An Efficient Regenerator Placement and Wavelength Assignment Solution --- p.55 / Chapter 2.3.4 --- Simulation Study of Proposed Algorithm --- p.60 / Chapter 2.4 --- Summary --- p.64 / Chapter Chapter 3 --- Adaptive Fault Monitoring in All-Optical Networks Utilizing Real-Time Data Traffic --- p.65 / Chapter 3.1 --- Introduction --- p.65 / Chapter 3.2 --- Adaptive Fault Monitoring --- p.68 / Chapter 3.2.1 --- System Framework --- p.68 / Chapter 3.2.2 --- Phase 1: Passive Monitoring --- p.70 / Chapter 3.2.3 --- Phase 2: Proactive Probing --- p.71 / Chapter 3.2.4 --- Control Plane Design and Analysis --- p.80 / Chapter 3.2.5 --- Physical Layer Implementation and Suggestions --- p.83 / Chapter 3.3 --- Placement of Label Monitors --- p.83 / Chapter 3.3.1 --- ILP Formulation --- p.84 / Chapter 3.3.2 --- Simulation Studies --- p.86 / Chapter 3.3.3 --- Discussion of Topology Evolution Adaptiveness --- p.93 / Chapter 3.4 --- Summary --- p.95 / Chapter Chapter 4 --- Conclusions and Future Work --- p.95 / Chapter 4.1 --- Conclusions --- p.96 / Chapter 4.2 --- Future Work --- p.97 / Bibliography --- p.98 / Publications during M.Phil Study --- p.105

Thesis (M.S.)--University of Hawaii at Manoa, 2007. / Includes bibliographical references (leaves 44-45). / viii, 45 leaves, bound ill. 29 cm

Thesis (Ph. D.)--Brigham Young University. Dept. of Electrical and Computer Engineering, 2006. / Includes bibliographical references (p. 101-106).

<p> This thesis studies the optical and electronic compensation for fiber nonlinearities based on the theory of Volterra expression. Signals propagating through optical fibers suffer from both linear and nonlinear distortion. In this thesis, we first construct an approximate inverse of fiber systems based on the theory of pth-order inverse of Volterra expansion. For a fully dispersion compensated fiber system H with a second-order dispersion profile f32 (z) and a total length of L, if the input field is real, we show that the inverse can be approximated by a system K with an inverted seconder-order dispersion profile -/32 ( z-L), while keeping all the other parameters the same. We then further develop the scheme by adding an optical phase conjugator ( OPC) in the middle of the transmission line. More specifically, the inversion of a fully dispersion compensated N-span fiber system H with a second-order dispersion profile /32 (z) and a total length L, is realized using an OPC followed by another N-span system K with an inverted seconder-order dispersion profile -f32(z-L), while keeping all the other parameters the same. In this way the original input optical signals can be recovered exactly. Our analytical and numerical simulation results show that the scheme works well for both single-channel systems and WDM systems. For electronic compensation techniques, we examine a nonlinear intersymbol interference (ISI) canceler based on Volterra theory, which was proposed first for voiceband data transmission, and apply it to optical fiber systems here, for the first time to our knowledge. The canceler is able to compensate nonlinear ISI caused by the cross product of both precursor and post cursor. </p> / Thesis / Master of Applied Science (MASc)

This thesis reports original work on suppression of transient gain excursions in an erbium-doped fibre amplifier (EDFA). The work presented in this thesis is a detailed investigation of four closed-loop systems that control the EDFA gain dynamically. The performance of the four closed-loop systems is evaluated by analytical work, supplemented by computer simulations and insystem measurements performed on a hardware EDFA. In addition, a stability analysis of the four closed-loop systems is presented. In the stability analysis presented in this thesis, nonlinear nature of the four closed-loop systems is taken into consideration. In the stability analysis, in addition to proving that the four closed-loop systems considered are stable, it is proven that for any practical values of the EDFA gain at the initial time of observation, the EDFA gain is restored to the desired value in steady state. These outcomes of the stability analysis are supported by simulation results and experimental results. Errors in system modelling, change in the operating point of the nonlinear closed-loop system, and measurement noise are important aspects of practical implementations of systems that control the EDFA gain dynamically. A detailed analysis of the effects these practical aspects have on the performance of the four closed-loop systems considered is presented. The analysis is validated using computer simulations and experimental measurements. In most of the work reported in the literature on controlling the EDFA gain, controllers that include feedforward and/or feedback components are employed. In the traditional approaches to combining the feedforward and the feedback components, large transient excursions of the EDFA gain can still occur due to errors in the control provided by the feedforward component. In this thesis, a novel approach to combining the feedforward and the feedback components of the controller is presented. Based on the analytical work, the computer simulations and the experimental work presented in this thesis, the novel approach provides a significant reduction in the excursions of the EDFA gain in the transient period.