等幅均匀复用OTDM信号的单路和群路时钟提取

提出了针对等幅均匀复用的光时分复用信号进行全光时钟提取的一种新方案,理论上分析了该方案的可行性,并给出了各次谐波时钟频率分量大小的表达式.实验上利用该方案成功地从等幅均匀复用的8×2.5 GHz信号中提取出了2.5 GHz单路时钟和20 GHz群路时钟光脉冲.此技术可应用于高速OTDM信号的时钟提取.     

Error-free OTDM demultiplexer using the supercontinuum spectrum-slicing induced clock signal

We experimentally demonstrate an 80-Gb/s optical time-division multiplexing (OTDM) demultiplexing system based on the cross-phase modulation (XPM) effect in high-nonlinearity fibers. The message carried by OTDM signal is loaded onto the probe signal by sampling the OTDM packet with a 10-GHz stable and controllable clock pulse train. The clock signal with ~ 11 ps pulse width is achieved by employing supercontinuum spectrum-slicing technique, which is distinct from that based on mode-locked lasers. The demultiplexed signal is obtained by filtering out the XPM-induced spectral sidebands of the probe signal. The OTDM demultiplexer based on this novel technique shows excellent performances and contributes to a bit error rate of as low as 10⁻⁹.     

光时分复用系统中单路时钟的提取

提出利用复用信号的时候不均匀性,采用主动光纤锁模激光器,直接从复用后的信号中提取出复用前的时钟光脉冲。考虑到电的时分复用与光的时分复用在机理上的一致性,故初步复用时分复用信号进行实验,成功地从时分复用信号中得到了复用前的时钟光脉冲。此处电的时分复用所得的结论适用于光的时分复用。     

Novel Technique for All-Optical Clock Extraction Using Fiber Bragg Gratings

We demonstrate a simple passive technique, using phase shifted fibre Bragg gratings, for extraction of optical clock signals from RZ optical data signals . The generation of an optical clock signal at 12.5 GHz from a 12.5 Gbs RZ optical data stream is experimentally demonstrated with simulation of optical clock extraction at 10 GHz fro m 40 Gbs OTDM data streams .     

Novel scheme of clock recovery for high-speed OTDM signals based on stimulated Brillouin scattering

A new but simply implemented optical clock recovery scheme for optical time-division multiplexing （OTDM） systems based on stimulated BriUouin scattering （SBS） effect is presented and demonstrated experimentally. According to the unequal-amplitude even-multiplexed OTDM signals, the frame clock is extracted. In addition, the clock with multiple tributary rates is recovered from 160-Gb/s OTDM signal in simulation by utilizing the clock recovery module.     

Tone Modulation in a Passive OTDM Multiplexer for Clock Recovery from a 160 Gbit/s OTDM Signal

Tone modulation in a passive OTDM multiplexer for clock recovery from a 160-Gbit/s OTDM signal by using a base-rate receiver is demonstrated. We performed synchronous demultiplexing in back-to-back arrangement and optical sampling after 320-km transmission.     

Performance of a 4×10 Gbit/s optical time domain multiplexed system using SMZ switching

Optical time division multiplexing (OTDM) is emerging and promising alternative for future high-speed photonic networks because of its ability to accommodate higher bit rate and flexible bandwidth. Among other factors the performance of an OTDM system largely depends upon the switching characteristics of a de-multiplexer (DEMUX). Symmetric Mach-Zehnder (SMZ) have been found to be most suitable than all the available de-multiplexing switches because of compact size, thermal stability, and low power operation. In this paper, we simulate four-channel OTDM systems (all channel multiplexer (MUX) and DEMUX) with a Mach-Zehnder modulator and SMZ DEMUX to investigate the impact of signal power, pulse width and control signal power on BER.     

Optical time division multiplexing at 160 Gbps using MZI switching

Many lower-speed data streams can be multiplexed into one high-speed stream by means of optical time division multiplexing (OTDM), such that each input channel transmits its data in an assigned time slot. The simulation is performed by a fast multiplexer switch (mux). The routing of different data streams at the end of the TDM link is performed by a demultiplexer switch (demux) and this demultiplexer is employed using MZI switch as it consists a semiconductor optical amplifier (SOA) and an optical coupler. In this paper four channel OTDM is simulated at 40 Gbit/s and further the impact of the signal power, pulse width and control signal power on BER is investigated.     

利用非线性光纤环路镜将20Gb/s的OTDM信号变换26nm

本文利用非线性光纤环路镜成功地将中心波长为1533.9nm的20Gb/s(8×2.5Gb/s)的OTDM信号变换到1553.3nm和1560.3nm,变换的最大间距达26nm,测量了变换后信号光的眼图和光谱图,并对实验结果进行了分析。     

基于光注入Fabry-Perot半导体激光器实现同步全光分路时钟提取与波长转换

提出了一种利用Fabry-Perot（FP）半导体激光器同步提取波长转换的分路光时钟的新方法,并对该方法进行了数值模拟和实验验证.光注入半导体激光器会产生非线性单周期振荡特性,利用交叉增益调制效应及对单周期振荡的微波锁频效应,可从光时分复用信号中提取出波长转换的分路光时钟.采用一个FP半导体激光器作为全光分路时钟提取及波长转换器,数值模拟实现了从波长为1555 nm、速率为2×20 Gb/s的光时分复用信号中提取出波长转换为1550 nm、重复频率为20 GHz的分路光时钟,实验完成了从波长为155024 nm、重复频率为1236 GHz光脉冲信号中提取出相位噪声为-105 dBc/Hz的波长为154591 nm、重复频率618 GHz的分频光时钟.此外还详细研究了注入光功率、波长失谐、FP激光器偏置电流及纵模选择对光时钟提取的影响,实验结果和数值模拟结果符合.该方法在光时分复用混合波分复用通信系统中实现全光解复用及波长路由有着重要的应用价值. 关键词： 波长转换 时钟提取 光注入 非线性动力学     

4×10Gb/s OTDM系统中偏振模色散自适应补偿的研究

利用信号偏振度为反馈信号，基于可变步长最大值搜索算法实现了4×10?Gb/s 光时分复用 （OTDM）系统偏振模色散（PMD）自适应跟踪补偿实验.PMD补偿器为偏振控制器加可变时延 线的四自由度结构.最大差分群时延（DGD）补偿量为25?ps，即信号的一个比特周期，补偿 时间小于50?ms. 关键词： 偏振模色散 光时分复用系统 偏振度 自适应补偿     

Demonstration of an 8×10-Gb/s OTDM system

An 8×10 Gb/s optical time-division-multiplexing (OTDM) system was demonstrated with an electroabsorption modulator (EAM) based short pulse generator followed by a two-stage nonlinear compression scheme which generated stable 10-GHz, 2-ps full-width at half-maximum (FWHM) pulse train, an optoelectronic oscillator (OEO) that extracted 10-GHz clock with a timing jitter of 300 fs from 80-Gb/s OTDM signal and a self cascaded EAM which produced a switching window of about 10 ps. A back-to-back error free demultiplexing experiment with a power penalty of 3.25 dB was carried out to verify the system performance.     

Application of electroabsorption modulators for high-speed transmission systems

To achieve ultra-high bit rate signal beyond existing ETDM technology optical time division multiplexing (OTDM) is been used. In this paper the various applications of electroabsorption modulators in transmitters and receivers in ultra-high speed OTDM-based transmission systems is reviewed. Results of single channel and DWDM fiber transmission experiments are presented.     

Clock recovery from 40 Gbps optical signal with optical phase-locked loop based on a terahertz optical asymmetric demultiplexer

10 GHz clock recovery from 40 Gbps optical time-division-multiplexed (OTDM) signal pulses is experimentally demonstrated using optical phase lock loop based on a terahertz optical asymmetric demultiplexer (TOAD) with a local-reference-oscillator-free electronic feedback circuit. The clock pulse that was used as the control pulse had energy of 800 fJ and the SNR of the time-extracted 10 GHz RF signal to the side components was larger than 40 dB.     

Study on a Multiplexer a 40 Gb/s OTDM System

In a 4?0Gb/s OTDM system (optical time-division-multiplication) system, multiplexing devices are key devices. The time interval of four channels of the 40Gb/s OTDM system is 25ps respectively. If the time intervals are no accurate, will induce the system performance to degeneration. In order to make out OTDM device and carry out a transmission experiment in a 40Gb/s OTDM system, a kind of OTDM device is researched. This scheme be used to fabricate multiplex device. Also the device have been used to a 40Gb/s OTDM system. Our experimental results shows that, the multiplex device based on the six 1 optical fiber couplers can be used to multiple at a time domain.That make four 10Gb/s optical signals multiple to 40Gb/s. The time interval error of each of channels is not bigger than 1ps, inserted loss is smaller than 2dB.     

Realizing 20 Gbit/s OTDM Transmission over 50 km True-wave Fiber with Dispersion Compensation

20 Gbit/s OTDM transmission over 50 km true-wave fiber with dispersion compensation was realized for the first time in China. The power penalty is smaller than 8 dB. The following technology problems were solved: the generation and the compression of ultra-short optical pulse; low bits to high bits multiplexer; high bits to low bits demulitplexer; the clock extraction from high speed system, dispersion compensation.     

Realizing 20 Gbits OTDM Transmission over 50km Truewave Fiber with Dispersion Compensation

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Semiconductor mode-locked lasers as pulse sources for high bit rate data transmission

Semiconductor mode-locked lasers are evaluated as pulse sources for high bit rate data transmission. This chapter describes the requirements of OTDM sources for high bit rate data transmission, compares various OTDM source technologies, describes three semiconductor mode-locked laser cavity designs, explains the impact of timing jitter and amplitude noise on OTDM performance, illustrates how to characterize noise of OTDM sources using rf and optical techniques, shows how to interpret the noise measurements, and finally discusses semiconductor mode-locked laser cavity optimizations that can achieve low noise performance.     

A phase stable short pulse generator using a DPMZM and phase modulators for application in 160 GBaud DQPSK systems

A method of 40 GHz phase stable short pulses generation is experimentally demonstrated. It is based on a dual parallel Mach–Zehnder modulator (DPMZM) driven by only one electrical sinusoidal clock and two cascaded phase modulators. The generated pulses are characterized with full-width-at-half-maximum pulse width of 1.9 ps, extinction ratio of 27 dB, timing jitter of 36 fs and signal to noise ratio over 30 dB. The high quality and phase stability of the pulses are further experimentally verified in a 4 × 40 GBaud differential quadrature phase shift keying (DQPSK) optical-time-division-multiplexing (OTDM) system.     

Performance analysis of OTDM system in the presence of FEC using symmetric Mach-Zehnder switch

Optical time division multiplexing is an emerging and promising alternative for future high-speed photonic networks because of its ability to accommodate higher bit rate and flexible bandwidth. SMZ have been found to be the most suitable switching element than all the available de-multiplexing switches because of compact size, thermal stability, and low-power operation. In this paper, we simulate four channel OTDM systems (all-channel multiplexer and de-multiplexer) with a Mach-Zehnder modulator and an SMZ de-multiplexer to investigate the impact of FEC on the OTDM system. It is observed that the presence of FEC in OTDM transmission can greatly improve the system performance.