Access network survivability: an architecture approach for monitoring, protection and restoration in FTTH application

This paper presented a simple monitoring, protection switching, and fast restoration approach for fiber to the home passive optical network (FTTH-PON) using Access Control System (ACS). ACS is developed for centralized monitoring and failure detection from central office (CO) in downstream direction (from CO towards customer sides). The proposed system architecture incorporating low cost and enable the network service providers and field engineers to remotely control the testing module from anywhere in the world and automatically identify any fiber fault and address the failure location in the fiber field. Another unique function of ACS is to provide the activation for optical switching in a restoration scheme which implemented at the drop region of FTTH-PON. A protection device named Customer Protection Device that comprises of programmable optical switches will be employed at the customer sides, just before the optical network unit, for rerouting the disrupted signals to the protection line when failure occurs in the working line to ensure continuous service delivery to customers.     

Applications of large-scale optical 3D-MEMS switches in fiber-based broadband-access networks

Applications of non-blocking large-scale optical switches based on three-dimensional micro-electro-mechanical system (3D-MEMS) technology with small size and low power consumption are described for fiber-based broadband access networks. The low-loss and fast-switching 3D-MEMS switches offer remotely reconfigurable and automated operational solutions for access networks such as fiber management, preventative maintenance, monitoring, testing, and troubleshooting of a large number of end customers. Furthermore, the wavelength, data rate, and protocol-transparent nature of 3D-MEMS switches results in a future-proof optical distribution network design for future higher speed and higher capacity wavelength division multiplexing overlay upgrades over the passive optical network (PON). We show that large-scale 3D-MEMS switches deployed in PON environments can offer over an order of magnitude in capital and operational savings in comparison to manual patch panels (in deployed fiber hardware, real estate, and manual labor) with minimal impact on the overall network design.     

OCDMA over WDM PON-solution path to gigabit-symmetric FTTH

It will be revealed that a myth of deploying low bit-rate uplink fiber-to-the-home (FTTH) services while providing a high bit-rate downlink is wrong. Therefore, for the future broadband FTTH services, the focus should be on the capability to provide gigabit- or even multigigabits-per-second both in up- and downlinks, namely gigabit symmetric systems. Optical code-division multiple access (OCDMA) now deserves a revisit as a powerful alternative to time-division multiple access and wavelength-division multiple (WDM) access in FTTH systems. In this paper, the authors will first highlight the OCDMA systems. The system architecture and its operation principle, code design, optical en/decoding, using a long superstructured fiber Bragg grating (SSFBG) en/decoder, and its system performance will be described. Next, an OCDMA over WDM passive optical network (PON) as a solution for the gigabit-symmetric FTTH systems will be proposed. The system architecture and the WDM interchannel crosstalk will be studied. It will be shown that by taking advantage of reflection spectrum notches of the SSFBG en/decoder, the WDM interchannel crosstalk can be suppressed and can enable OCDMA over WDM PON to simultaneously provide multigigabit-per-second up- and downlinks to a large number of users.     

电力光纤到户光缆监测系统的设计

电力光纤到户工程是国家电网公司智能电网建设的重要组成部分,随着智能电网建设的不断推进,光纤到户部署的规模将不断扩大,网上光缆数量急剧增加,如何维护这些光缆是迫切需要解决的问题。电力光纤到户光缆监测系统采用了PON网络通信、光学测量、地理信息系统等技术,很好地解决了FTTx网络中PON光纤资源的监控,同时能兼顾对接入、汇聚、骨干层光缆网络的监测管理。通过集中的自动维护方式,系统能及时地反映光缆的运行状况,在光缆出现故障时,能够快速测试、准确定位。     

Connection anonymity analysis in coded-WDM PONs

A coded wavelength division multiplexing passive optical network (WDM PON) is presented for fiber to the home (FTTH) systems to protect against eavesdropping. The proposed scheme applies spectral amplitude coding (SAC) with a unipolar maximal-length sequence (M-sequence) code matrix to generate a specific signature address (coding) and to retrieve its matching address codeword (decoding) by exploiting the cyclic properties inherent in array waveguide grating (AWG) routers. In addition to ensuring the confidentiality of user data, the proposed coded-WDM scheme is also a suitable candidate for the physical layer with connection anonymity. Under the assumption that the eavesdropper applies a photo-detection strategy, it is shown that the coded WDM PON outperforms the conventional TDM PON and WDM PON schemes in terms of a higher degree of connection anonymity. Additionally, the proposed scheme allows the system operator to partition the optical network units (ONUs) into appropriate groups so as to achieve a better degree of anonymity.     

PON with Automatic Protection switching for high reliable communication

PON (Passive Optical Network) permits the economical deployment of FTTH (Fiber to the Home) networks by sharing a single optical subscriber line among multiple subscribers. Especially since 2002, the deployment of PON systems has grown rapidly. This paper introduces the current status of FTTH in Japan then proposes a redundant optical access system with APS (Automatic Protection Switching) over PON which enables PONs for FTTBus (Fiber to the Business).     

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.     

MPCP based active optical access network with PLZT high-speed optical switch

An active optical access network architecture with our newly developed PLZT ((Pb,La)(Zr,Ti)O₃) high-speed optical switch is introduced, with a view to realizing the next-generation high capacity scalable access network. This system is developed based on the latest IEEE standard of PON (10G-EPON; IEEE802.3av) in consideration of the coordination with future high capacity PON. PLZT high-speed optical switches are able to switch an optical signal at nano-second speed (<5-10 ns). Generally, the merits of using optical switches are increasing the number of subscribers and transmission distance easily, preventing malicious ONUs from interfacing with the communication between OLT and the other ONUs, realizing fast fiber and OLT protection/restoration and providing various services by controlling optical switches dynamically. This paper focuses on two key technologies; a PLZT optical switch and a new discovery process for active optical access network based on MPCP defined at IEEE802.3. A major challenge in designing active optical access network is supporting the discovery process of MPCP because it does not offer broadcast transmission unlike the regular PON. We propose here a new discovery process; it has been tested successfully in an implementation of our proposed system.     

Cost and quantity analysis of passive double-star optical-access-network facilities for broadband service multiplexing

In this paper, the authors propose the most suitable passive double-star network (PON) configuration for multiplexing more than two kinds of broadband service by wavelength division multiplexing (WDM) in optical access networks. They calculate the cost and number of facilities in outside plant and central offices by using the latest cost trend and investigate their dependence on certain structural conditions such as the number of splits, network configuration, and fiber structure, and service conditions such as multiplexing service number and service penetration. Moreover, the required network configuration for multiplexing more than three services was investigated. As a result, the most suitable PON network for cost-effective service provision and fiber to the home (FTTH) deployment was determined.     

HFC and PON-FTTH networks using higher SBS threshold singlemode optical fibre

Measurements showing improved RF video transmission are presented over a test-bed which replicates parts of a commercial hybrid fibre-coax (HFC) network using an optical fibre specifically engineered for fibre-to-the-home (FTTH) featuring +3 dB higher stimulated Brillouin scattering (SBS) threshold. Results validate improved system performance and increased reach for use in PON and FTTH architectures     

用PON技术实现FTTH的工程设计要点

主要讨论在利用无源光网络技术实现光纤到户（FTTH）的工程设计中遇到的相关问题，如FTTH的系统结构、组网方案、带宽的测算、光配线网的设计、最大传输距离的确定、回波损耗的要求，并提出有关解决方案。     

适用于FTTH的用户光缆建设方案初探

从PON的结构入手,分析了传统用户光缆网建设方案应用于基于PON的FTTH用户光缆网建设中存在的问题。从拓扑结构、光交、配纤方式等方面,提出改进模式,探讨适用于FTTH的用户光缆建设方案。     

Performance Limitations of Subcarrier Multiplexed WDM Signal Transmissions Using QAM Modulation

We theoretically investigate the performance limitations of subcarrier multiplexed (SCM) wavelength-division-multiplexing (WDM) systems using optical double-sideband (DSB) modulated, 16-quadrature amplitude-modulated (QAM) signals. The performance limitations are investigated using crosstalk power and SCM channel spacing for various transmission conditions, including impairment factors such as dispersion and fiber nonlinearities for a single wavelength channel first. The effects of WDM channel spacing on SCM systems with multiwavelength channels are also evaluated via the calculated bit error rate (BER) performance, based on the performance limitations found in the single-wavelength simulation. This enables us to provide guidelines for the design of SCM/WDM systems for fiber-to-the-home (FTTH) network in WDM–passive optical network (PON) architecture, based on the performance limitations.      

PON管理关键技术问题浅析

面向三重播放业务的需求,构建新一代的网络管理架构、优化IT系统和维护体系是当前运营商PON建设和维护的重点和难点.本文面向PON,尤其是FTTH规模发展情况下的运维能力提升,探讨了PON管理中的一系列关键技术问题,包括PON EMS管理、北向接口及网管流程以及省级集中管理平台功能要求等.     

Low‐Cost,Low‐Power,High‐Capacity 3R OEO‐Type Reach Extender for a Long‐Reach TDMA‐PON

This paper proposes a low‐cost, low‐power, and high‐capacity optical‐electrical‐optical‐type reach extender that can provide 3R frame regeneration and remote management to increase the reach and split ratio with no change to a legacy time division multiple access passive optical network. To provide remote management, the extender gathers information regarding optical transceivers and link status per port and then transmits to a service provider using a simple network management protocol agent. The extender can also apply to an Ethernet passive optical network (E‐PON) or a gigabit‐capable PON (G‐PON) by remote control. In a G‐PON, in particular, it can provide burst mode signal retiming and burst‐to‐continuous mode conversion at the upstream path through a G‐PON transmission convergence frame adaptor. Our proposed reach extender is based on the quad‐port architecture for cost‐effective design and can accommodate both the physical reach of 60 km and the 512 split ratios in a G‐PON and the physical reach of 80 km and the 256 split ratios in an E‐PON.     

Protection switching and local area network emulation in passive optical networks

This paper proposes and experimentally demonstrates an automatic-protection-switching (APS) mechanism against distribution fiber breaks in passive optical networks (PONs). The protection of optical-network units (ONUs) that are located at the customer premises is carried out by monitoring the distribution fiber using the traffic that is transported among the customers in the PON. This configuration emulates a local area network (LAN) over the existing PON while facilitating the switching of signal transmissions to a predetermined protection path in an event of a distribution fiber break. As failure detection and APS are performed independently by each ONU in a distributed manner, the processing complexities and delays are reduced at the central office (CO). The restoration of the traffic transported between the CO and an ONU in the event of the distribution fiber break is performed by interconnecting adjacent ONUs and carrying out signal transmissions via an independent but interconnected ONU. Such a protection mechanism enables multiple adjacent ONUs to be simultaneously protected by a single ONU utilizing its maximum available bandwidth. This paper experimentally verifies the feasibility of the proposed protection mechanism in conjunction with two different LAN-emulation schemes with a 1.25-Gb/s upstream baseband transmission to the CO and a 155-Mb/s LAN data transmission on a radio-frequency carrier. The experimental results obtained from both schemes are compared, and the power budgets are calculated to analyze the scalability of each scheme.     

Study of passive optical network monitoring based on non-OTDR

Aiming at the defects of passive optical network （PON） monitoring based on optical time domain reflectometry （OTDR） technology, we research the non-OTDR monitoring technology. The coding scheme based on periodic encoder monitoring is discussed, and its limitation is analyzed. On this basis, the monitoring technology based on optical code division multiple access （OCDMA） is put forward. We analyze the feasibility of monitoring scheme based on PON of OCDMA, design a monitoring plan, and then use OptiSystem to simulate the design. The results of simulation and bit error rate （BER） analysis show that this monitoring technology can overcome the deficiencies of OTDR and distinguish the monitoring signals of different fiber branches clearly, which meets the demands for high beam split ratio of multi-user communication.     

下一代光无源网络(NG-PON)主流技术

FTTH是未来宽带接入网发展的必然趋势,无源光网络(PON)技术以其纯介质网络特性获得越来越广泛的认可及部署,被认为是FTTH的最佳解决方案.文章综述了下一代无源光网NG-PON,扼要地介绍、分析了10G EPON、WDM-PON的工作原理和实现方案,提出了NG-PON的演进思路.     

光纤通信在市内接入网的应用

先说明市内接入网的单位用户和住家用户两大类使用通信和电视、交互型和分配型业务的要求不相同，相应地对光纤传输的应用须作不同的考虑，文中认为；光纤从市内交换局直连办公大楼是合乎现实需要的，而对于居民住家，宜选用光纤连至路边或光纤与同轴结合和适当利用无源光网络等方案，俟将来时机成熟才实行光纤连至每一家，文末有概括总结，说明接入网不同于长途网，接入网的光纤系统可以使用常规单模光纤，工作于波长1．3μm，而光放大器和波分多路系统不是普遍需要，但光电子集成在光端机中是必要的。     

一种融合EPON和GPON的接入方案

无源光网络(PON)突破了传统的点到点解决方法的局限,一直被认为是光接入网中最具发展前景的技术.由于光接入网应用环境复杂多样,PON应用技术也呈现出多样化的特点.以太网无源光网络(EPON)和千兆无源光网络(GPON)是其中两种具有代表性的接入技术.文章根据光纤到户实际工程的需要,论述了一种融合EPON和GPON技术的接入方案.