Influence of Even-Order Dispersion on Super-Sech Soliton Transmission Quality under Coherent Crosstalk

The transmission speed of optical network strongly depends on the impact of higher order dispersion. In presence of coherent crosstalk, which cannot be otherwise controlled by optical filtering, the impact of higher order dispersions becomes more pronounced. In this paper, the general expressions, that describe pulse deformation due to second- and fourth-order dispersions in a single-mode fiber, are given. The responses for such even-order dispersions, in presence of coherent crosstalk, are characterized by waveforms with long trailing edges. The transmission quality of optical pulses, due to both individual and combined influence of second- and fourth-order dispersions, is studied in this paper. Finally, the pulse shape and eye diagrams are obtained

PERFORMANCE ANALYSIS OF WSXC AND WIXC SSM OXC IN WDM OPTICAL NETWORKS

The impact of inband crosstalk on an optical signal passing through optical cross-connect nodes (OXC’s) in wavelength division multiplexing (WDM) optical network, is studied from the equation of electric field with crosstalk and the corresponding current. The analysis has been done for two SSM (space switching matrix) OXC architecture namely WSXC & WIXC where later one has full wavelength conversion capability. Although WIXC attenuates more crosstalk though it is found that depending on the values of optical propagation delay differences, coherent time of lasers and time duration of one bit of the signal, the required power penalty in WIXC may be greater than that of WSXC in some cases. The analysis has been performed on the measures of Bit Error Rate (BER) and Power Penalty

Investigation of the Effects of Chirped RZ Signals in Reducing the Transmission Impairments in R-SOA-Based Bidirectional PONs

Distributed and concentrated reflections represent the two main limitations in reflective-semiconductor optical amplifier (R-SOA)-based passive optical networks (PONs). In this paper, we experimentally discuss how the use of chirped signals in centralized light seeding bidirectional PON can increase the resilience of the system against those two types of reflections. An experimental comparison of the performance of a highly chirped return to zero (RZ) modulation format and the nonreturn to zero is given. Error-free operation is achieved down to 10 dB of signal to crosstalk ratio in presence of distributed reflection, when the upstream signal is highly chirped RZ signal. The same chirped modulation leads to a tolerance of more than dB network return loss due to concentrated reflections. Finally, we assess also the system feasibility of a R-SOA-based full-duplex PON where both the upstream and the downstream are modulated signals

Crosstalk Characterization and Reduction in Power Lines

We propose a technique of crosstalk reduction through power lines. This crosstalk reduction technique uses the pseudo-matched impedances’ method that determines the characteristic parameters of the chosen line through the transmission lines’ theory. Besides, we establish the telegrapher's equations to determine the characteristic impedances of the line. Further, two types of lines are employed here to apply the pseudo-matched impedances’ method. The far-and near-ends crosstalk are measured with two strategies known as Simulink diagram and Matlab code. The Simulink diagram of the power line provides crosstalk curves and the Matlab code directly returns crosstalk values. It appears that the crosstalk has a reduction rate between 20 and 50% compared to previous investigations using pseudo-matched impedances in literature. Moreover, the variation of two different types of impedances leads to a crosstalk reduction rate that approaches 99%.Published By: Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP) © Copyright: All rights reserved

Interference analysis for optical wireless communications in Network-on-Chip (NoC) scenarios

Optical wireless (OW) communications, besides being of great interest for indoor and outdoor applications, have been recently proposed as a powerful alternative to the existing wired and wireless radio frequency (RF) interconnects in network-on-chips (NoCs). Design and analysis of networks with OW links require a careful investigation of cross-link interference, which impacts considerably the efficiency of systems that reuse the same channel for multiple transmissions. Yet, there is no comprehensive analysis of interference for OW NoCs, and the analyses of crosstalk in optical waveguide communications usually rely on synchronous data transmissions. A novel framework for the analysis of on-chip OW communications in the presence of cross-link cochannel interference and noise is proposed, where asynchronous data transmissions are considered. Self-beating of interfering signals is also considered, which was often neglected in previous literature. The bit error probability (BEP) for arbitrary number of interfering sources is derived as a function of signal-to-noise ratio (SNR), interference powers, detection threshold and pulse shaping, using both exact and approximation methods. The proposed analysis can be applied to both noise- and interference-limited cases, and enables a system designer to evaluate reuse distance between links that share the same optical carrier for simultaneous communication in NoCs

Adaptive routing and wavelength assignment in all-optical networks

In WDM all-optical networks without wavelength conversion capabilities, signals must travel on the same wavelength over long distances. During transmission the signal quality gets degraded due to linear and non-linear physical layer impairments resulting in high BER. Many PLI aware RWA algorithms have been proposed in the literature, which consider the effect of the impairments on the signal quality. We consider the effect of component crosstalk and ASE noise. The adaptive RWA algorithm presented incorporates QoS information at both the routing and wavelength assignment steps to mitigate the effect of crosstalk. Different routing strategies are used in the algorithm to compare the computational complexity and the blocking performance of the network

Impact of physical layer impairments on SDM networks based on ROADM nodes

Current transport optical networks are approaching its capacity limits, mainly due to new applications and services that require a huge amount of resources. To increase the network capacity, multiband solutions, that exploit the unused capacity of actual fibers, in particular the L-band, are being currently commercially explored. However, this strategy is assumed as a short to medium term solution. A long-term solution is to use spatial-division multiplexing (SDM) in the optical domain, which leads to the concept of SDM-based optical networks. In this work, different SDM switching architectures (spatial, spatial-wavelength, wavelength, fractional space-full wavelength) are studied and compared in terms of cost per bit, power consumption and flexibility. For the switching architectures with spatial and spatial-wavelength granularities (the architectures that have superior performance), the most relevant physical impairments (PLIs) (amplifiers noise, non-linear interference, narrowing penalty due to filtering and in-band crosstalk) are analytically studied, for a SDM reconfigurable optical add-drop multiplexer (ROADM) cascade. Furthermore, a Monte Carlo simulation is used to assess more rigorously the PLIs effects on the performance of SDM ROADMs, with spatial-wavelength switching architecture, in cascade. The main difference, regarding PLIs, between the single spatial channel ROADM architecture and the SDM ROADM architectures is the enhanced effect of in-band crosstalk. For cascaded ROADMs with 16 directions, 19 spatial channels and filtering isolation of -25 dB, the in-band crosstalk can lead to a 2 dB optical signal-to-noise ratio penalty. Due to this penalty, the signal crosses less 9 ROADMs than in a single spatial channel ROADM architecture.As redes óticas de transporte atuais estão a aproximar-se do seu limite de capacidade devido às novas aplicações e serviços que requerem uma maior quantidade de recursos de rede. Uma possível solução de curto a médio prazo para a falta de recursos é o uso de múltiplas bandas da fibra, para além da banda C. Uma solução a longo prazo será o uso de multiplexagem com divisão no espaço (SDM) no domínio óptico. Neste trabalho são estudados, o custo por bit, consumo de energia e flexibilidade, das diferentes arquiteturas SDM (no espaço, no espaço e comprimento de onda, no comprimento de onda, fracionada no espaço e completa no comprimento de onda). Para as arquiteturas com granularidades no espaço e no espaço e comprimento de onda estuda-se analiticamente os efeitos das principais limitações do nível físico (PLIs) (ruído dos amplificadores, interferência não-linear, penalidade de filtragem e diafonia homódina), para cascatas de multiplexadores óticos de inserção/extração reconfiguráveis (ROADMs). Usa-se uma simulação Monte Carlo para calcular mais rigorosamente os efeitos das PLIs na arquitetura com granularidade no espaço e comprimento de onda. A principal diferença, em termos de PLIs, entre uma rede SDM e uma rede com um único canal espacial é o efeito da diafonia homódina. Para uma rede com 16 direções, 19 canais espaciais e isolamento dos filtros de -25 dB, a diafonia homódina causa uma penalidade na relação sinal-ruído óptica de 2 dB e o sinal atravessa menos 9 ROADMs que numa rede com apenas um canal espacial

Internetworking architectures for optical network units in a wavelength division multiplexed passive optical network.

Zhao, Qiguang.Thesis (M.Phil.)--Chinese University of Hong Kong, 2007.Includes bibliographical references (leaves 72-76).Abstracts in English and Chinese.Chapter Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Telecommunications network hierarchy --- p.2Chapter 1.2 --- PON architectures for access networks --- p.4Chapter 1.2.1 --- TDM-PON --- p.5Chapter 1.2.2 --- WDM-PON --- p.7Chapter 1.3 --- Motivation of this thesis --- p.8Chapter 1.4 --- Outline of this thesis --- p.11Chapter Chapter 2 --- Previous Internetworking Architectures for Optical Network Units in Passive Optical Networks --- p.12Chapter 2.1 --- Introduction --- p.13Chapter 2.2 --- Previous internetworking architectures with ONU-broadcast capabilityChapter 2.2.1 --- Virtual ring network construction --- p.14Chapter 2.2.2 --- Reflection mechanism employing a FBG --- p.15Chapter 2.2.3 --- Loop-back mechanism in TDM-PON --- p.16Chapter 2.3 --- Previous internetworking architectures with ONU-VPGs formation capability --- p.17Chapter 2.3.1 --- E-CDMA application --- p.17Chapter 2.3.2 --- SCM technique --- p.18Chapter 2.3.3 --- Reflective waveband grouping mechanism --- p.20Chapter 2.4 --- Previous protection scheme for internetworking architectures --- p.21Chapter 2.4.1 --- Local ring protection in TDM-PON --- p.21Chapter 2.5 --- Summary --- p.22Chapter Chapter 3 --- Novel Internetworking Architecture with ONU-Broadcast Capability in a WDM-PON --- p.24Chapter 3.1 --- Introduction --- p.25Chapter 3.2 --- Network topology and wavelength assignment --- p.26Chapter 3.3 --- Operation principle --- p.27Chapter 3.4 --- Experimental demonstration --- p.31Chapter 3.5 --- Power budget and scalability --- p.34Chapter 3.6 --- Summary --- p.36Chapter Chapter 4 --- Novel Internetworking Architectures with ONU- VPGs Formation Capability in a WDM-PON --- p.37Chapter 4.1 --- Introduction --- p.38Chapter 4.2 --- Novel architecture with ONU-VPGs formation based on RF tone technique --- p.39Chapter 4.2.1 --- Introduction --- p.39Chapter 4.2.2 --- Network topology and wavelength assignment --- p.40Chapter 4.2.3 --- Media access control protocol: CSMA/CA protocol --- p.42Chapter 4.2.4 --- Experimental demonstration --- p.43Chapter 4.2.5 --- Discussion --- p.47Chapter 4.2.6 --- Summary --- p.49Chapter 4.3 --- Novel architecture with ONU-VPGs formation in optical layer --- p.51Chapter 4.3.1 --- Introduction --- p.51Chapter 4.3.2 --- Network topology and wavelength assignment --- p.51Chapter 4.3.3 --- Operation principle --- p.54Chapter 4.3.4 --- Experimental demonstration --- p.56Chapter 4.3.5 --- Discussion --- p.58Chapter 4.3.6 --- Summary --- p.65Chapter 4.4 --- Comparisons --- p.66Chapter 4.5 --- Summary --- p.67Chapter Chapter 5 --- Summary and Future Works --- p.68Chapter 5.1 --- Summary of the thesis --- p.69Chapter 5.2 --- Future works --- p.70LIST OF PUBLICATIONS --- p.71BIBLIOGRAPHY --- p.7