320 Gbit/s光时分复用系统研究

针对高速率OTDM(光时分复用)系统中的一些关键技术问题,如时钟提取、时分解复用和色散补偿等,提出了8×40Gbit/s的OTDM系统技术方案。结果表明,通过选择合适的时钟提取方式和基于对称性色散位移光纤的色散补偿技术,能够实现在一个时隙内对每个信道的40 Gbit/s归零码信号的解复用,且解复用后的信号质量较好。该系统实现了320Gbit/s OTDM通信。     

OTDM系统时钟提取和解复用研究北大核心

为了从高速OTDM(光时分复用)信号中提取出支路时钟并实现解复用,实现高速光信号与相对低速电信号之间的接口,首次展示了一种基于商用的MZM(马赫-曾德调制器)和PolM(偏振调制器)级联的OEO(光电振荡器)实现从2×40GBaud/s OTDM信号中提取支路时钟并同时解复用的实验方案。利用这种改进的OEO,成功地从2×40GBaud/s的OTDM DQPSK(差分四相相移键控)调制格式的高速光信号中提取出了40GHz电时钟,该时钟的相位噪声在10kHz频偏处达到-98.62dBc/Hz,与微波源(Agilent Technologies,E8267D)的相位噪声质量几乎相同。这种OEO还同时实现了从OT-DM信号中解复用出两个支路信号的功能,即将160Gbit/s的PRBS(伪随机二进制序列)OTDM信号成功解复用为两路高质量的80Gbit/s支路信号。     

4×10Gb/s OTDM复用与解复用结构优化技术研究

基于40Gb/s OTDM复用结构,利用电吸收调制器(EAM)及时钟提取模块组成的解复用模型,实现了10GHz时钟分量的提取和信号的解复用.针对OTDM复用后信号的非等幅现象以及对应频谱中含有10GHz、20GHz等其他频谱分量的情况,进行了仿真分析及讨论.同时通过实验对不同的时钟提取与解复用结构提取出的时钟信号的质量进行了对比,优化了解复用结构,得到了抖动更小的帧时钟信号.     

GaAs/GaAlAs行波激光放大器的研制及特性研究

近年来,半导体激光放大器(SLA)发展很快,SLA的光—光直接信号放大特性在波分复用(WDM)、频分复用(FDM)等长距离大容量传输系统中非常有吸引力。 按SLA的工作方式和结构特点可把其分成三种类型:法布里型(FP—SLA),注入     

基于光滤波器的光时分复用光谱压缩技术实验

提出了解复用窗口匹配滤波器的概念,分析了利用光带通滤波器提高光时分复用(OTDM)频谱效率的光谱压缩技术。基于自制的40Gb/sOTDM复用器,采用电吸收调制器(EAM)及时钟提取模块组成的反馈环路解复用模块,以阵列波导光栅(AWG)作为电吸收采样窗口(EASW)的匹配滤波器对4×10Gbit/sOTDM信号进行光谱压缩,实现了无误码传输100km及传输后的解复用。实验结果表明,AWG的使用使得OTDM信号的频谱效率提高至4倍。     

WDM/OTDM混合光网络系统性能仿真研究

基于optisystem详细讨论如何构建一个完整的WDM/OTDM混合光网络仿真系统.仿真中信源采用经过RZ调制的信号,波长转换采用基于SOA-XGW的全光转换方式,传输采用色散补偿光纤补偿传输过程中的色散,解复用采用PLL光时钟提取方法.经过对仿真结果图的分析,表明经过以上改进处理可以改善WDM/OTDM混合光网络的传输性能,为混合光网络的商用提供参考.     

光时分复用为高速网络带来新希望

DL7统的基于电调制的商用TDM系统速率已可达10Gb八,一些公司将在明年推出40Gb／S的产品。但是,为了进一步提高单信道的速率,必须在光域内再进行一次复用,即光时分复用（OTDM）。与波分复用（WDM）不同,WDM是将多个速率较低的信道分别复用到不同的波长上在同一根光纤上传输,而OTDM则是将这些信道在时域内加以复用,其结果是在一个单波长上传送速率极高的数据流。OTDM一般通过称为比特交织的过程实现。将重复频率为IOGHz的高速脉冲序列分成N路,每一路分别以数据信号进行调制,然后分别加以延迟,相邻两路的延迟时间等于原…     

WDM/OTDM混合光网络节点中数据格式转换的数值模拟

本文研究了基于半导体光放大器交叉增益调制(XGM -SOA)效应的波长转换器在WDM/OTDM混合光网络节点数据格式转换中的应用。利用通用的分段动态模型,模拟了速率为10Gbit/s两信道波分复用信号的时分复用和经色散移位光纤传输及色散补偿后的时分复用信号的解复用。转换后信号变换宽度宽,消光比性能好。模拟结果为系统设计和混合光网络交换节点信息处理提供了理论依据。     

电信辞库

光时分复用 光时分复用(OTDM)技术是当比特率超过10Gbit/s时,为了克服高速电子器件和半导体器件直接调制能力的限制所采用的扩大传输容量的复用方式。它是用多个电信道信号调制具有同一个光频的不同光信道,经光学复用后在同一根光纤传输,在接收端用光学方法把它们解复用出来的扩容技术。这种方法使用宽带光电器件代替了高速电子器件,因而避开了因电子器件造成的瓶颈。     

4×10GHz的0TDM系统时钟提取及解复用实验研究

对4×10GHz光时分复用(OTDM)系统中,基于LiNbO3调制器的注入光电混合振荡器的时钟提取方法进行了实验验证,提取的时钟抖动小于0.5ps。从实验上分析了入射光功率对时钟信号的影响。同时利用提取的时钟实现了基于电吸收调制(EAM)晶体的各个信道的解复用,解复用信号基本无邻道串扰。     

A Hybrid OTDM Scheme With Enhanced Demultiplexing Performance

We propose a novel hybrid optical time-division multiplexing (OTDM) approach, which contains hybrid modulation formats of return-to-zero on-off keying and return-to-zero differential-phase-shift keying, and investigate its demultiplexing performance. Compared with conventional OTDM with homogenous modulation format, the target demultiplexed channel in a hybrid OTDM signal suffers from much less degradation due to the possible crosstalk from the adjacent channels. We experimentally demonstrate 84.88- to 10.61-Gb/s hybrid OTDM demultiplexing and achieve a relatively wide switching window, which cannot be realized by using the conventional OTDM. Moreover, experimental results at 42.44 Gb/s show a much larger tolerance against timing misalignment in demultiplexing, which further validates the improved demultiplexing performance by using the hybrid OTDM scheme.     

Simultaneous all-optical demultiplexing and regeneration based onself-phase and cross-phase modulation in a dispersion shifted fiber

Simultaneous demultiplexing and regeneration of 40-Gb/s optical time division multiplexed (OTDM) signal based on self-phase and cross-phase modulation in a dispersion shifted fiber is numerically and experimentally investigated. The optimal walkoff time between the control pulse and OTDM signal is obtained by numerical simulation. Our experiment also shows that it is an effective method for realizing simultaneous demultiplexing and regeneration when used in the middle of a system or in the receiver with a proper walkoff time     

RZ-DPSK OTDM demultiplexing using fibre optical parametric amplifier with clock-modulated pump

Optical demultiplexing for a 40 Gbit/s RZ-DPSK OTDM signal using a fibre optical parametric amplifier with a sinusoidal-clock-modulated pump is experimentally demonstrated. Less than 1.3 dB power penalty and around 30 dB gain are obtained for all four demultiplexed channels. Superior performance is obtained for the demultiplexed tributaries in RZ-DPSK OTDM systems compared with those in RZOOK OTDM.     

All-optical TDM data demultiplexing at 80 Gb/s with significant timing jitter tolerance using a fiber Bragg grating based rectangular pulse switching technology

We demonstrate the use of fiber Bragg grating based pulse-shaping technology to provide timing jitter tolerant data demultiplexing in an 80 Gb/s all-optical time division multiplexing (OTDM) system. Error-free demultiplexing operation is achieved with /spl sim/6 ps timing jitter tolerance using superstructured fiber Bragg grating based 1.7 ps soliton to 10 ps rectangular pulse conversion at the switching pulse input to a nonlinear optical loop mirror (NOLM) demultiplexer comprising highly nonlinear dispersion shifted fiber (HNLF). A 2-dB power-penalty improvement is obtained compared to demultiplexing without the pulse-shaping grating.     

高速光时分复用系统的全光解复用技术

作为高速光信号处理应用的一个分支,全光解复用技术涉及到半导体非线性光学多方面的问题,是实现高速光时分复用（OTDM）系统的关键技术之一。文章对现有的OTDM系统的全光解复用技术进行了综述,较为详细地描述了两类主流技术的工作原理,对两者的优缺点做了剖析,介绍了潜在的基于更高速全光开关的解复用新技术,并探讨了全光解复用技术的演进思路。     

In-band clock distribution concept for ultra-high bit rates OTDM system

A novel clock distribution concept based on inband phase-modulated pilot insertion is demonstrated.This method avoids the need for an ultrafast phase comparator and a phase-locked loop in the receiver.Experimental results show that the clock can be successfully extracted from 160Gbit/s optical time-division multiplexing (OTDM) data signal and employed for demultiplexing of 40Gbit/s tributaries.The in-band clock distribution introduces 1.5dB of power penalty with an error-free performance.     

40-Gb/s OTDM to 4×10 Gb/s WDM conversion in monolithic InPMach-Zehnder interferometer module

Transformation of high bit-rate optical time-domain multiplexed (OTDM) signals into a multitude of lower bit-rate wavelength-division-multiplexed (WDM) channels is demonstrated by means of a single monolithically integrated indium phosphide Mach-Zehnder interferometer with semiconductor optical amplifiers in its arms. Full demultiplexing of 10-Gb/s OTDM signals into 4×10-Gb/s WDM channels is demonstrated. Bit-error-rate penalties are below 1.5 dB for polarization independent signal conversion throughout the 1.55-μm wavelength range     

Timing-jitter-free demultiplexing of an all-optical signal processor based on the intensity-dependent self-wavelength conversion of Raman solitons

An all-optical signal processor based on the self-wavelength conversion of Raman solitons is described. The processor consists of an erbium-doped fiber amplifier (EDFA), a highly nonlinear fiber, and an optical bandpass filter. The timing-jitter-free demultiplexing of the processor was demonstrated by an 80-km transmission experiment. Error-free bit error rate (BER) performance was achieved. Transmitted fourfold optical time-division multiplexing (OTDM) signals with a large timing jitter of about 16 ps for an OTDM signal interval of 25 ps were demultiplexed to 9.95-Gb/s signals without signal degradation.     

Optical time-division multiplexing for very high bit-ratetransmission

Optical time-division multiplexing (OTDM) extends and expands the well-known techniques of electrical time-division multiplexing into the optical domain. In OTDM, optical data streams are constructed by time-multiplexing a number of lower-bit-rate optical streams. Opportunities for very high-speed transmission and switching are created by removing limitations set by the restricted bandwidth of electronics and by capitalizing on the inherent high-speed characteristics of optical devices. An overview of recent work in optical time-division multiplexing and demultiplexing is presented. Design considerations affecting system architecture are described. Emphasis on the factors that limit system performance, such as crosstalk between multiplexed channels. Examples of very high bit-rate optical time-division multiplexed system experiments using short pulses from mode-locked semiconductor lasers and high-speed Ti:LiNbO₃ waveguide switch/modulators are presented     

All-optical time-division demultiplexing experiment withsimultaneous output of all constituent channels from 100 Gbit/s OTDMsignal

The successful demonstration of all-optical time-division demultiplexing is reported, wherein all 10 Gbit/s constituent channels are simultaneously demultiplexed with no error from a 10×10 Gbit/s OTDM signal. A multichannel demultiplexer based on cross phase modulation (XPM)-induced frequency shift in an optical fibre, called MOXIC, is used