WDM-PON的无色ONU技术

波分复用无源光网络(WDM-PON)实现了点到点的连接,可为每个用户提供专有波长,被普遍认为是未来宽带接入的代表性技术.WDM-PON的关键在于:要求采用低成本、"无色"的光网络单元(ONU),以避免波长选择器件所带来的安装、运营以及维护成本的增加.本文简要分析了3种WDM-PON的无色ONU的实现方法,指出无色ONU是构建WDM-PON的一种较理想的解决方案.     

WDM-PON技术研究和实现方案

首先对时分复用无源光网络(TDM-PON)与波分复用无源光网络(WDM-PON)系统结构和工作原理作对比,得出WDM-PON技术优势,随后介绍了ONU波长固定的WDM-PON系统、ONU宽光源频谱分割WDM-PON系统,然后着重分析了采用再调制技术的两种方案,并对每种方案的优缺点作了简要分析,最后分析了WDM-PON的应用前景.     

基于FP激光器设计WDM-PON光源 低成本ONU光源理论浅析

在设计WDM-PON系统时，ONU端光源是其关键技术之一，传统的ONU光源价格比较昂贵而且较易受环境以及温度的影响，本文提出了一种新型WDM-PON的ONU光源和一个采用了该光源的WDM-PON系统结构，并对光源的性能进行了研究。这种光源是通过向FP激光二极管注入窄带ASE来实现的，并且该二极管无需冷却器和隔离器。     

基于RSOA的WDM-PON调制技术研究

简要介绍了WDM-PON的系统结构和工作原理.在ONU.端用RSOA代替光源可以实现ONU的“无色化”.通过仿真实现了DPSK/DPSK调制的WDM-PON系统,能够满足低误码率要求,提高系统性能,为WDM-PON系统的应用提供一种选择.     

基于动态波长分配的WDM-PON技术研究

WDM-PON是未来宽带光接入网的发展趋势,基于动态波长分配的WDM-PON在系统安全和网络带宽升级等方面具有独特优势.文章介绍了WDM-PON的基本结构及运行原理,着重对基于动态波长分配的WDM-PON作了研究,并对其中涉及到的一些关键技术(如多波长光源、ONU光源和MAC协议等)作了深入分析和探讨,总结了WDM-PON的发展现状,提出了应用前景.     

WDM-PON下的动态调度算法研究

波分复用无源光网络(WDM-PON)采用虚拟点对点通信,是光网络发展的一种必然趋势.而基于反射式半导体光放大器(RSOA)的再调制WDM-PON系统通过在ONU处用RSOA做调制器替代光源,实现了ONU的“无色化”技术方案,具有巨大的技术优势.以该结构为基础,比较静态顺序和批处理两种调度算法,并进行仿真分析.     

基于OFDM的WDM-PON网络架构的研究

提出了一种基于OFDM的WDM-PON网络架构,采用梳状光谱发生器作为OLT的光源,在ONU端使用反射式半导体光放大器(RSOA)来充当WDM-PON中ONU的重调制器。该网络架构具有低成本、易实现和高速率等优点。     

基于注入锁定的WDM—PON系统研究

WDM-PON规模应用的技术难点主要集中在光器件方面,特别是ONU光源。本文对基于FP-LD和RSOA注入锁定的WDM-PON进行了分析,研究目标是实现无色的上行传输。     

下一代多波长光接入网关键技术分析

介绍了WDM-PON系统的基本结构以及运行原理,重点分析和探讨了其中涉及到的关键技术,主要包括多波长光源、波分复用器、ONU光源、接收机等光器件方面的问题.此外,还对光网络的保护和恢复以及如何承载广播业务等关键问题进行了深入探讨.最后,分析了WDM-PON未来的研究方向,并提出了应用前景.     

WDM-PON技术研究及实现方案(本期优秀论文)

简要介绍了WDM-PON的系统结构和工作原理,比较分析了WDM-PON技术的优势,进而研究了WDM-PON系统中的无色ONU技术和WDM/TDM混合型结构技术,并综合这两种技术提出了一种新的WDM-PON的实现方案,为将来WDM-PON接入网系统的发展提供了参考.     

PON系统规模部署的主要方式和关键技术

主要介绍了FTTB／FTTH等场景的接入提供方式及设备类型选择、语音业务提供方式、网管架构等重点问题,以及QoS、VLAN、组播、ONU认证、光链路保护、光链路测试诊断、异常发光ONU检测及控制、ODN智能化等关键技术。     

A self-seeded reflective SOA-based optical network unit for optical beat interference robust WDM/SCM-PON link

We have proposed and experimentally demonstrated a novel optical source configuration that uses a self-seeded reflective semiconductor optical amplifier (RSOA) as an optical network unit (ONU) in a wavelength division multiplexed/subcarrier multiplexing (SCM)-passive optical network (PON). A fiber Bragg grating (FBG) was used to obtain a single longitudinal mode of the RSOA. The proposed ONU configuration is simple, cost-effective, and effective regardless of wavelength allocation. Additionally, it would be robust for optical beat interference (OBI) noise. As the ONU is composed only of an RSOA and FBG, the self-seeded RSOA, due to the strong self-injection caused by the reflection of the FBG, has a broad optical spectrum. A self-homodyne apparatus method was performed in order to demonstrate the robustness of the self-seeded RSOA in OBI. To confirm the validity of the proposed scheme, a 16-quadrature amplitude modulation transmission experiment was performed in a 10-, 20-km optical access link with an SCM frequency of 1 GHz. An error vector magnitude of less than 4% for 2 Msps was successfully obtained through the transmission experiment.     

Degradation of Bi-Directional Single Fiber Transmission in WDM-PON Due to Beat Noise

This paper presents a general formulation for the impact of back-reflection in wavelength division multiplexing-passive optical networks (WDM-PON) access networks. The analysis is applied to various wavelength-independent optical network unit (ONU) configurations such as amplified spontaneous emission (ASE)-locked Fabry-Perot (FP) lasers, reflective semiconductor optical amplifiers or injection locked FP using the downstream signal. The power penalty due to beat noise and its dependence on relative intensity noise, transmitter linewidth, and receiver bandwidth is investigated. The optimal gain at the ONU that minimizes the effect of beat noise is also found. The results show that the power penalty decreases as the linewidth of the the optical line terminal (OLT) and ONU light source increase.     

10Gbit/s EPON非对称ONU光模块的设计

文章重点介绍和讨论了10 Gbit/s EPON(以太网无源光网络)非对称ONU(光网络单元)光模块的组成和关键技术,特别是发射硬件电路的构成和数字APC(自动光功率控制)的原理,同时,也介绍了接收部分的实现,给出了合理的设计方案且通过实验进行验证.实验结果表明,采用该方案设计出的光模块能满足国际标准要求,可以广泛应用...     

Impact of backreflection on upstream transmission in WDM single-fiber loopback access networks

This paper investigates the impact of backreflection lights on upstream transmission in wavelength division multiplexing (WDM) single-fiber loopback access networks, where a WDM light source is located at the central office (CO) and each optical network unit (ONU) includes an optical modulator with optical amplifiers. This study considers backreflection lights from two sources, the continuous wave (CW) light at the CO (Reflection-I) and the modulated signal at the ONU (Reflection-II). It is confirmed, for the first time, that the impact of Reflection-II increases strongly with ONU gain. To estimate the impact of these backreflection lights, a simple intensity noise estimation scheme is presented. This scheme clarifies that the acceptable transmission line losses is 10 dB for 1.25 Gb/s under the optical return loss (ORL) of -32 dB.     

基于同步传输的射频光网络单元设计

RFoG技术在HFC网络双向改造中存在明显的优势,越来越多的运营商采用RFoG组网方案,但是RFoG的射频光网络单元由于光突发模式采用电平控制ONU的开通与关断,造成实现困难。为此,给出了一种基于同步传输的射频光网络单元设计方法,将回传信号数字化,采用和CMTS相同的时分复用技术(TDMA)来控制ONU反向光发射的"突发",从而达到在任一给定的时点只允许一个ONU与CMTS头端保持通信,以弥补其不足。     

Wavelength reused upstream transmission scheme for WDM passive optical networks

A novel technique facilitating wavelength reused upstream transmission in a WDM passive optical network, eliminating wavelength source at ONUs, is proposed and experimentally demonstrated. A subcarrier frequency is used for downstream transmission and the pure optical carrier is filtered and reused for upstream transmission. The scheme requires only simple baseband receivers at both ONU and OLT terminals.     

Reliable wide-area wavelength division multiplexing passive optical network accommodating gigabit ethernet and 10-Gb ethernet services

This paper proposes and demonstrates a reliable wide-area wavelength-division-multiplexing passive optical network (WDM-PON) with a wavelength-shifted protection scheme. This protection scheme utilizes the cyclic property of 2/spl times/N athermal arrayed-waveguide grating and two kinds of wavelength allocations, each of which is assigned for working and protection, respectively. Compared with conventional protection schemes, this scheme does not need a 3-dB optical coupler, thus leading to ensure the large loss budget that is suited for wide-area WDM-PONs. It also features a passive access node and does not have a protection function in the optical network unit (ONU). The feasibility of the proposed scheme is experimentally confirmed by the carrier-distributed WDM-PON with gigabit Ethernet interface (GbE-IF) and 10-GbE-IF, in which the ONU does not employ a light source, and all wavelengths for upstream signals are centralized and distributed from the central office.     

PON业务常见故障的处理

无源光网络(PON,Passive Optical Network)采用无源光分/合路器或光耦合器分配/汇聚各光网络单元(ONU,Optical Network Unit)信号的光接入网。PON系统系由光线路终端(OLT,Optical Line Terminal)、光分配网(ODN,Optical Distribution Network)、光网络单元(ONU)组成的信号传输系统,简称PON系统。目前主流PON综合接入系统根据采用的技术分为以太网无源光网络(EPON,Ethernet Passive Optical Network)和吉比特无源光网络(GPON,Gigabit-capable Passive Optical Networks)。     

Adaptive Optical Network Unit for Point-to-Point and PON Systems Based on Gigabit Ethernet

This paper proposes an optical network unit (ONU) that works in point-to-point (P2P) optical access systems as well as passive optical network (PON) systems and so reduces the operational expenditure of optical access networks in the full FTTH era. First, we discuss its design and implementation; after clarifying the requirements for the adaptive ONU, we describe how it should work while focusing on Gigabit-Ethernet-based P2P and PON systems. Next, we study its feasibility through experiments on a prototype. Also, we provide some additional considerations regarding the implementation and future application of the adaptive ONU.