一种用于塑料光纤接入网的多优先级控制协议设计

提出一种基于光码分多址(OCDMA)技术的塑料光纤接入网的多优先级控制协议.由于受传输误码率的限制,常规的光码分多址系统只允许有限个用户传输数据或接入网络,为了解决用有限的码字来实现多于码字数目的多媒体工作站间的信息通信,这种多优先级的控制协议通过使用预约和随机分配算法可以有效地解决信道冲突和目的地址的冲突问题, 该协议可以支持多媒体信息传输中各类信息不同的时间延迟要求.另外,在该接入网中,每个光网络单元均设有两套光编码器和光解码器,一套用于控制信道,另一套用于各个数据信道.利用本文提出的协议对塑料光纤接入网的网络吞吐量和平均延时时间进行了数值分析和仿真实验,结果证明了这种多优先级控制协议的有效性和高效性.     

激光器驱动和激光器之间的高速连接

光纤接入网以其高速度,大容量、低功耗等优点,成为接入网的重要发展方向,低成本的高速光发射机成为光纤接入的一个关键.相对于外调制激光器.直接调制激光器因为调制简单、成本低,成为光发射机的首选方案.激光器和激光器驱动之间高速的连接,是实现直接调制光发射机的关键技术之一.理论分析了激光器驱动器输出的偏置电流和调制电流之间的关系,得出了实现偏置电流和调制电流稳定的条件.分析了激光器和激光器驱动之间高速连接存在的问题,选择电容耦合的方式,利用高速印刷线路板(PCB)布线技术,实现了 2.5 Gb/s的直接调制激光器的研制.     

用于塑料光纤接入网的三优先级控制协议设计

为了解决用有限的码字来实现多于码字数目的多媒体工作站间的信息通信,提出一种基于光码分多址(Optical Code Division Multiple Access,OCDMA)技术的塑料光纤接入网的多优先级控制协议. 该协议通过使用预约方案和仲裁算法可以有效地解决信道冲突和目的地址的冲突问题,可以支持多媒体信息传输中各类信息不同的时间延迟要求.通过建立一个离散马尔科夫链模型对塑料光纤接入网的网络吞吐量和平均延时时间进行了数值分析和仿真实验,结果证明,这种多优先级控制协议能够适应多媒体网络中各类业务对信号时延要求的不同进行信道的优先级分配.     

高频调制大功率窄线宽分布反馈光纤激光器

研制了一种窄线宽光纤激光器.在有源相移光栅后加一段掺铒光纤,当用980 nm抽运光注入时,首先形成了分布反馈(DFB)光纤激光器,而残余抽运光将铒纤中铒离子从基态抽运到了激发态,对DFB激光实现了有效放大,实现了对残余抽运光的充分利用,节省了功耗、降低了成本;同时利用温控技术克服了DFB光纤激光器的温度敏感问题;将相移光栅黏贴于片状压电陶瓷(PZT)的表面实现了高频调制.实验研制的激光器的最高调制频率为2 kHz、输出功率为15.6 dBm,线宽为300 kHz. 关键词： 分布反馈光纤激光器 窄线宽 大功率 高频调制     

增益半导体光放大器的特性

为满足半导体光放大器（SOA）在光纤到户FTTH系统接入网中的广泛应用,提出了基于光纤光栅外腔反馈型GC-SOA结构的全光增益机制,窄线宽激光光源经可变衰减器、隔离器和光纤光栅注入到SOA中,SOA的输出光经隔离器和光纤光栅送至光谱分析仪,通过光纤光栅反馈输入SOA形成钳制激光。对GC-SOA的阈值特性、增益特性及开关特性进行分析,结果表明:当注入电流小于GC-SOA的阈值电流时,增益随注入电流的增加而增加;当注入电流大于GC-SOA的阈值电流后,其增益不再随注入电流的变化而变化,实现了SOA的增益稳定,使SOA的饱和输出功率得到了提高。     

基于半导体光放大器的光脉冲压缩方案的研究

对一种基于半导体光放大器(SOA)和普通单模光纤的光脉冲压缩方案进行了理论分析和实验验证.建立了该方案的理论分析模型,并在此基础上数值模拟了光脉冲的传播过程.计算结果表明,通过合理选取单模光纤的长度,可使50 ps光脉冲压缩到5 ps.实验表明利用普通单模光纤群速度色散导致的脉冲啁啾抵消SOA自相位调制引起的脉冲啁啾,实现了色散补偿及脉冲压缩.     

基于重构等效啁啾制作光纤光栅编解码器的光码分多址系统实现

在光码分多址(OCDMA)系统中，光纤布拉格光栅(FBG)编解码器是极具竞争力的核心器件，满足光接入网低成本、高性能的要求. 将重构等效啁啾 (REC) 技术制作的FBG作为编解码器运用于OCDMA系统. 实验采用一对511个码片、编码速率为6.4×10⁹/s的FBG编解码器，在编码匹配的情况下能恢复出输入信号，与编码非匹配的情况相比获得了8 dB的功率增益.这为REC技术制作的编解码光栅在OCDMA系统中的应用提供了实验依据. 关键词： 光纤布拉格光栅 光码分多址 重构等效啁啾 编解码器     

40 Gbit/s非等幅编码光时分复用传输系统

4× 10Gb s非等幅编光时分复用 (OTDM)传输系统采用增益开关分布反馈式激光器 (GS DFB)产生超短光脉冲 ,通过色散补偿光纤 (DCF)和梳状色散光纤链 (CDPF)实现了脉冲的线性和非线性压缩 ;利用啁啾光纤光栅实现色散补偿 ;在接收端 ,利用电吸收调制器 (EAM)实现了光时分复用信号的解复用 ;同时采用非等幅编码方案提取帧时钟。整个系统经过 12 2km的G .6 5 2光纤传输之后 ,误码率小于 10 - 9。     

纤维光学 光纤及其传输理论

TN252006010430城域网和接入网发展需要的低水峰单模光纤=Low waterpeak SMF a demand for increasing metro and access net-works[刊,中]/Shashi Kant(印度斯德雷特光科技有限公司,印度马哈拉斯特拉奥兰加巴德(431136)),HarishTaneja…∥光通信研究.—2005(4).—42-45介绍一种最新研制的光纤,其在整个宽工作带,包括在(1380±3)nm上都具有低水峰。低水峰光纤与粗波分复用(CWDM)系统比用标准单模光纤(SMF)的同一系统所用的信道间隔宽33%。经过恶劣的环境试验证明,低水峰光纤具有稳定的抗氢气引起的衰减性能,可确保现场安装的低水峰光…     

基于半导体光放大器四波混频效应的多种调制格式的波长转换实验

实验报道了利用半导体光放大器(SOA)的四波混频(FWM)效应实现多种码型的波长转换.其中对于非归零(NRZ)信号实现了从单信道到三信道的多波长转换.调制速率从10 Gb/s到40 Gb/s均实现多波长转换.对于归零(RZ)信号分别实现了20 Gb/s和40 Gb/s的RZ格式的波长转换和40 Gb/s的载波抑制归零(CSRZ)格式的波长转换,利用光纤布拉格光栅(FBG)作为带陷滤波器消除共轭光和抽运光之间的串扰.对于非归零差分相移键控(NRZ_DPSK)信号分别实现了20 Gb/s和40 Gb/s的波长转换,利用实验室自制的光纤延时干涉仪进行NRZ-DPSK信号的解调.基于FWM效应的转换光的输出消光比大于7 dB,转换后消光比退化约为3 dB.     

A novel multipriority reservation protocol for plastic optical fiber access network

In this paper, a novel multipriority reservation protocol for plastic optical fiber access network based on optical code division multiplexing access (OCDMA) technology is proposed. Conventional OCDMA system only allows finite units to transmit and access simultaneously according to the number of channels. The protocol is proposed to resolve this problem. By using the reservation scheme and a distributed arbitration algorithm, channel collision and destination conflict can be avoided. The protocol can efficiently support the transmission of multimedia messages that require the different time-delays. At the same time, each optical network unit is equipped with a fixed optical encoder/decoder that is always tuned to channel for control and the tunable optical encoder/decoder that is tuned to any of channel for data. The network throughput and average delay have been investigated by numerical analysis and simulation experiments. It is shown that the multipriority reservation protocol in this POF access net     

基于光码分多址技术的塑料光纤局域网动态控制协议设计与仿真

本文提出一种基于光码分多址(OCDMA)技术的塑料光纤局域网的动态控制协议,用有限的码字来实现多于码字数目的多媒体工作站间的信息通信,而且当工作站数目增加时无需重新对网络进行初始化,工作站可随时加入网络.该协议特别适合可变信息长度的多媒体通信网络,通过数值分析和仿真实验,证明该动态控制协议的有效性和高效性.     

适用于同步光码分多址通信系统的同步光码及其全光可调编/解码器

异步光码分多址通信系统,要求用户地址码具有好的循环自相关和互相关特性,因此,系统中的用户数受到很大的限制;而对同步光码分多址通信系统,只要求光地址码是非循环相关意义下的准正交,从而可实现较大的用户数,因此具有广阔的应用前景.实现同步光码分多址的关键之一是同步光码的设计和可调光编/解码器的实现.本文介绍了同步光码的构造方法,给出了同步光码的构造过程,分析了码的容量,提出了全光可调同步光码编/解码器的实现方法.     

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.     

一种基于全息光处理器的可调光编码/解码器设计

提出了一种基于全息光处理器的可调光编码-解码器的实现方案.这种新结构的可调光编码/解码器减小了硬件实现的复杂性,降低了成本和功耗,便于集成.     

Fast frequency modulation optical code division multiple access communication system

An optical fast frequency modulation code division multiple access communication system is proposed. In this system, an electrically controlled tunable optical filter (TOF) is used to encode the modulated broadband light source. The code depends on the function set to the controller. Two-dimensional code named functional code is also proposed based on a shifted sine function. The function defines the dynamic coding pattern of the central wavelength of the transmitted narrowband optical signal. Thus, the system will allow for an easy reconfiguration of the transmitter without the need for sophisticated encoder. At the receiver, a synchronized TOF with the same function is used as a decoder. The performance of this system is shown to be better compared with a fast frequency hopping and a spectral amplitude coding systems.     

Realization of 2-D OCDMA network using EDW code

The attraction towards two-dimensional optical code division multiple access (2D-OCDMA) systems has increased due to its potential in enhancing the performance of optical access networks and producing optical code-based signals. 2D-OCDMA network systems enable better bit-error-ratio (BER) performance as well as increase the number of supportable users in the optical network. Time-spreading wavelength-hopping is one of the many techniques that has been proposed for 2D-OCDMA. In this paper, we present the simulative study of a 2D-OCDMA system. The developed time-spreading, wavelength-hopping network utilizes enhanced double weight (EDW) code which has enhanced properties such as a cross-correlation value of 1 and has a simple encoder/decoder design. The output BER was satisfactory at above 10^?9 at data rate of 1.25 Gbps for 20 km distance with the ITU-T G.652 standard single mode optical fiber for 3 users.     

Tunable 2D time-wavelength optical CDMA encoder for differentiated service provisioning

We propose and demonstrate a reconfigurable tunable encoder for two-dimensional time-wavelength optical code division multiple access (OCDMA). This encoder is capable of creating 2D codes with variable code weight, enabling differentiated service provisioning. The demonstrated novel scheme uses ultra-fast optical delay lines and all-optical sampling while operating at 115 Gchip/s. Our proposed architecture provides an all-optical method of varying the code weight on a bit-per-bit basis, while maintaining the core architecture of a tunable OCDMA encoder.     

基于步进啁啾光纤光栅的编解码器的OCDMA系统性能分析

对基于步进啁啾光纤光栅编解码器的OCDMA系统性能进行了分析,通过数值模拟得到系统性能与系统参数满足的关系,为改善系统性能提供可靠的依据.本文是对基于步进啁啾光纤光栅的OCDMA频阈相位编码一文的深化.