A Wavelength and Bandwidth Assignment Algorithm to Support Guaranteed Bandwidth Levels in Hybrid Time Division Multiplexing/Wavelength Division Multiplexing Ethernet Passive Optical Networks

Abstract

A novel bandwidth assignment algorithm in wavelength division multiplexing Ethernet passive optical networks, called a dynamic wavelength assignment service level agreement, is proposed to efficiently provide subscriber differentiation. Simulation results show that the dynamic wavelength assignment service level agreement outperforms other bandwidth allocation algorithms in wavelength division multiplexing Ethernet passive optical networks, as it makes a fairer bandwidth distribution than other methods and is able to overcome the non-allowed packet fragmentation of the Ethernet passive optical network standard. Consequently, it greatly increases the achieved throughput and always ensures a minimum guaranteed bandwidth to every priority subscriber. Furthermore, the new algorithm obtains lower mean packet delay and packet loss rate for the highest priority subscribers when compared with other bandwidth distribution schemes in wavelength division multiplexing Ethernet passive optical networks.     

Costs of Fiber-to-the-Home Passive Optical Network Unbundling

Abstract

This work considers different unbundling options for local loop unbundling in order to provide multi-operator access and consider the economical impact for the fiber-to-the-home next-generation access entrants to deploy such alternatives. It is shown that deploying wavelength division multiplexing networks is an efficient strategy to perform local loop unbundling while upgrading the gigabit passive optical network for the new era where high bandwidths are necessary for satisfying customer demand. In areas with a high population density, wavelength division multiplexing techniques are the most suitable for entrant operators to access the incumbent's network and provide service.     

Energy-Efficient Next-Generation Passive Optical Networks Based on Sleep Mode and Heuristic Optimization

Abstract

In this article, an energy-efficiency mechanism for next-generation passive optical networks is investigated through heuristic particle swarm optimization. Ten-gigabit Ethernet–wavelength division multiplexing optical code division multiplexing–passive optical network next-generation passive optical networks are based on the use of a legacy 10-gigabit Ethernet–passive optical network with the advantage of using only an en/decoder pair of optical code division multiplexing technology, thus eliminating the en/decoder at each optical network unit. The proposed joint mechanism is based on the sleep-mode power-saving scheme for a 10-gigabit Ethernet–passive optical network, combined with a power control procedure aiming to adjust the transmitted power of the active optical network units while maximizing the overall energy-efficiency network. The particle swarm optimization based power control algorithm establishes the optimal transmitted power in each optical network unit according to the network pre-defined quality of service requirements. The objective is controlling the power consumption of the optical network unit according to the traffic demand by adjusting its transmitter power in an attempt to maximize the number of transmitted bits with minimum energy consumption, achieving maximal system energy efficiency. Numerical results have revealed that it is possible to save 75% of energy consumption with the proposed particle swarm optimization based sleep-mode energy-efficiency mechanism compared to 55% energy savings when just a sleeping-mode-based mechanism is deployed.     

A Techno-Economic Study on the Outside Plant Cost of Current and Next-Generation Fiber-to-the-X Deployments

Abstract

A techno-economic study on the outside plant costs of fiber-to-the-X infrastructures is presented in this article. Standardized passive optical network and active optical network technologies, implemented in fiber-to-the-home architectures, are presented/compared in terms of costs. Future architectures based on passive optical networks are investigated, their outside plant infrastructure, and corresponding costs are reviewed. Cost comparisons of fiber-to-the-X infrastructures reveal significant differences. Besides fiber-to-the-node being the less costly, it is shown that the cost of high splitting ratio passive optical network fiber-to-the-home infrastructures is not increasing linearly with the splitting ratio. The highest splitting ratio is not always the one with the largest savings percentage. Referring to current and future fiber-to-the-home access network architectures/technologies, the flexibility of wavelength division multiplexing/time division multiplexing passive optical networks is estimated to reach a 40% reduction in outside plant cost compared with the home run architecture.     

Performance Analysis of Duty-Cycle Division Multiplexing over Wavelength Division Multiplexing System

Abstract

Performance optimization of a duty-cycle division multiplexing system over 8- and 40-channel wavelength division multiplexing networks is reported in this article. The modified duty-cycle division multiplexing system with optical domain multiplexing using a dual-drive Mach–Zehnder modulator is simulated with two and three users per wavelength. Using conventional dispersion compensation, the 40 × 40-Gbps system with two and three users per channel can support 240 and 160 km of transmission distance, respectively. The dispersion management technique based on a chirped fiber Bragg grating is proposed for a 40 × 3 × 13.33-Gbps duty-cycle division multiplexing/wavelength division multiplexing system that allows double the transmission distance compared to conventional technique.     

A Novel Wavelength Division Multiplexing Passive Optical Network Based on Self-Seeding Light Source and Doubling Wavelength-Utilized Rate

Abstract

A wavelength-utilized rate-doubled wavelength division multiplexing passive optical network based on a self-seeding light source is proposed. The effect of distributed fiber length and power division ratio on the upstream-signal power is analyzed; the result indicates that raising the power division ratio can increase the upstream-signal power when it is lower than 0.86. The power difference between upstream signals caused by the length difference of distributed fibers is also expanded with power division ratio; thus, the power division ratio should be decreased to a proper level to reduce the power difference when the length difference is too large.     

Bidirectional Wavelength Reconfigurable Module Based on Tunable Fiber Bragg Grating and Remote Pump Amplifier

Abstract

This article presents a novel bidirectional wavelength reconfigurable optical network utilizing a remotely pumped erbium-doped fiber amplifier and tunable fiber Bragg gratings. The system is experimentally demonstrated at a 10-Gb/s per channel over 20-km fiber span that verifies the metro-network range system performance. The achieved power penalty is less than 1 dB when compared to the back-to-back transmission link. An example of practical application where the proposed module is used as an add/drop multiplexer and a remote node in the bidirectional wavelength division multiplexing passive optical network system is described.     

Optical Filters Using Optical Multi-Layer Structures for Optical Communication Systems

Abstract

In this article, light reflection spectrums for different one-dimensional multi-layer structures are obtained. Optical reflectivities for periodic, superperiodic, and quasiperiodic structures have been calculated using the transfer matrix method. PBGs of each structure have been obtained using the optical reflectivity pattern. From a comparison of reflectivity and standard dense wavelength division multiplexing grids, it is demonstrated that narrow and dense band filters can be built from generalized Fibonacci quasiperiodic structures. Reflectivity of these structures contains bands that meet the ITU-T dense wavelength division multiplexing standard. Reflectivity of other multi-layer structures has poor or less potential to be used in dense wavelength division multiplexing systems.     

Overview of DWDM/ODC Project

Abstract

This article introduces the main achievements resulting from the DWDM/ODC project. The five areas of research activity within the DWDM/ODC project cover some of the main issues of design and development of dense wavelength division multiplexing systems for transparent optical networks. These issues are: performance assessment with arbitrary optical filtering; performance of signaling formats; dispersion compensation strategies for directly and externally modulated systems in presence of nonlinear transmission-induced degradation; and the impact of noise and crosstalk in the extent of transparent optical networks. All five areas of research activity have contributed significantly to a better understanding of the limitations present in dense wavelength division multiplexing systems.     

Advanced Optical Network

The following article describes an advanced dense wavelength division multiplexing (DWDM) Optical Network developed by L-3 Photonics. The network, configured as an amplified optical bus, carries traffic simultaneously in both directions, using multiple wavelengths. As a result, data distribution is of the form peer-to-multi-peer, it is protocol independent, and it is scalable. The network leverages the rapid growth in commercial optical technologies, including wavelength division multiplexing (WDM), and when applied to military and commercial platforms such as aircraft, ships, unmanned and other vehicles, provides a cost-effective, low-weight, high-speed, and high noise-immune data distribution system.     

Crosstalk Elimination in Dense Wavelength Division Multiplexing Networks: Implementation and Theory

Abstract

Data traffic for multiple independent data channels can be simultaneously transmitted over a dense wavelength division multiplexing network with complete segregation. A limiting amplifier applied to each channel after the optical to electrical conversion eliminates crosstalk.     

基于正交频分复用无源光网络的动态带宽分配算法研究

介绍了一种应用于未来大容量、多业务接入场景下的称为光正交频分复用无源光网络的下一代接入网技术,并提出了一种基于此结构的称为基于服务质量需求的固定周期流水线轮询动态带宽分配算法.该算法通过应用二级带宽分配机制、带宽预申请机制和最小带宽申请优先原则等方法,有效地保障了在大容量、多业务接入场景下各个业务不同的服务质量需求.为研究其性能,建立了该算法的仿真模型并进行了对比仿真.仿真结果显示该算法以低时延和低抖动有效地支持快速转发业务,同时平衡了确保转发业务和尽力而为业务之间的优先性和相对公平性,并且实现了不同光网络单元间的同优先级业务带宽分配的公平性.与传统的动态带宽分配算法算法相比,基于服务质量需求的固定周期流水线轮询动态带宽分配算法具有执行效率高、算法复杂度低、性能良好等优点,并且能够更好地适应光正交频分复用无源光网络的特性,发挥网络最大的性能.     

基于正交频分复用无源光网络的动态带宽分配算法研究

介绍了一种应用于未来大容量、多业务接入场景下的称为光正交频分复用无源光网络的下一代接入网技术,并提出了一种基于此结构的称为基于服务质量需求的固定周期流水线轮询动态带宽分配算法.该算法通过应用二级带宽分配机制、带宽预申请机制和最小带宽申请优先原则等方法,有效地保障了在大容量、多业务接入场景下各个业务不同的服务质量需求.为...     

Evolving the Optical Transport Network Management to Integrate Multiple Technologies and Services

Abstract

Optical networks are evolving at a fast pace from traditional synchronous digital hierarchy/synchronous optical network (SDH/SONET) and wavelength division multiplexing (WDM) infrastructures, used by client network layers in overlay mode, to a converged multi-service and multi-technology network able to transport traditional time division multiplexing (TDM) traffic and new packet traffic in a flexible way. Alcatel-Lucent is leading the network transformation required by network providers to offer data transport while guaranteeing the same quality and reliability typical of classical transport services. The introduction of new data communication services requires an evolution of the network management platform that needs to integrate new management applications associated with the new technologies and services. The resulting network has to be integrated from service provisioning and management system viewpoints to optimize its use and to reduce the in-field modifications of the transport network. This article describes specificities in the management of multi-service networks, identifying the management architecture able to support the rapid evolution of such environment.     

Hybrid WDMA/OCDM system with the capability of encoding multiple wavelength channels by employing one encoder and one corresponding optical code

<正>A hybrid wavelength division multiple access(WDMA)/optical code division multiplexing(OCDM) system is proposed,where the optical code is not the same as the address of every optical network unit(ONU); rather,the code is a virtual fiber of hybrid passive optical network(PON).To our knowledge,this is the first report analyzing a single encoder/decoder with a single corresponding optical code being exploited to encode/decode multiple wavelength signals simultaneously.This system enables OCDM to become transparent to ONU so that the existing wavelength division multiplexing(WDM) PON can be upgraded. Thus,redesigning the optical line terminal and ONU can be easily accomplished,and greatly decreasing the number of encoder/decoder becomes possible.In experiment,we only employ two encoder/decoder pairs to combine two WDM-PONs in one fiber.Simulation results confirm the feasibility of the proposed system.     

Ultra-High-Capacity Passive Optical Network Systems with Free-Space Optical Communications

Abstract

This article experimentally demonstrates a hybrid fiber–free-space passive optical network that enables high spectral density, aggregated capacity, and total throughput through ultra-dense wavelength-division multiplexing baseband and radio-over-fiber channels. Ultra-dense wavelength-division multiplexing 10-Gb/s Nyquist-shaped 16-ary quadrature amplitude modulation, 10-Gb/s radio-over-fiber orthogonal frequency-division multiplexing, and 8.75-Gb/s baseband orthogonal frequency-division multiplexing signals per user were transmitted through a maximum 40-km passive optical network, which includes a 6-m free-space optics link with acceptable performance.     

Optimum Compensator Positioning to Reduce Four-Wave Mixing in Wavelength Division Multiplexing Optical Communication Systems Using Dispersion-Managed Fibers

Abstract

The impact of the compensator's location along the optical fiber on a variation of four-wave mixing power penalty is investigated theoretically and numerically for dispersion-managed fibers in wavelength division multiplexing systems. The power penalty is analyzed for fibers with different attenuation coefficients and lengths, and the optimum positions for the compensator along the fiber is discussed in cases of both dispersion compensation of each fiber section between two amplifiers and whole-compensation.     

Wavelength tunable optical time-domain reflectometry based on wavelength swept fiber laser employing two-dimensional digital micro-mirror array

We demonstrate a cost effective wavelength tunable optical time-domain reflectometry (OTDR) for wavelength division multiplexing passive optical networks (WDM-PON). In order to realize the unique wavelength tunable optical time-domain reflectometry (OTDR), the wavelength swept fiber laser was developed by a digital micro-mirror array device (DMD), and the correlation OTDR (COTDR) technique was used. We successfully detected the fault location at the remote node fibers with 20 m resolution and fast wavelength setting speed of ∼15 μs in conventional band (C-band).     

Photonics applications in switching: An ATM optical node

Abstract

An ATM optical node architecture that carries out cell routing and buffering by photonic means, controlled by electronic circuits, is presented. An evolutionary approach, where cell aggregation and compression are introduced to achieve a large throughput, with a high performance, is also described. And we report experimental results that demonstrate the feasibility of all the relevant photonic functions, based on advanced optoelectronic devices, namely: fast wavelength reassignment, suitable for multigigabit operation, based on fast tunable lasers and semiconductor optical amplifiers; high bit rate packet storage in a multiwavelength fiber loop memory including fast optical gates; dynamic wavelength selection, based on distributed feedback (DFB) filters with nanosecond tuning response; and all optical demultiplexing of multigigabit/s time division multiplexing (TDM) signals by means of saturated semiconductor optical amplifiers.     

Enhanced performance for 10 Gb/s long reach RSOA based WDM-PON by using power pre-emphasized OFDM signal

An extended reach 10 Gb/s wavelength division multiplexing passive optical networks (WDM-PONs) system based on reflective semiconductor optical amplifier (RSOA) is proposed by using power pre-emphasized orthogonal frequency division multiplexing (OFDM) signal. Experimental results show that the proposed technique can effectively enhance the system performance against the limited bandwidth and chirp induced fading effect from direct modulation of RSOA. The receiver sensitivity is improved by 5 dB at the limit of BER for forward error correction (FEC) code over the 60 km and 85 km fiber transmission without any dispersion compensation module.