Analysis of a DPSK soliton transmission system

We present a closed form expression to analyse the error performance of a differential phase-shift keying (DPSK) digital modulation format in an optical soliton communication system. In the analysis we include the effect of Gordon-Haus jitter, which is mainly due to the amplified spontaneous emission noise of the amplifiers. Gordon-Haus jitter is found to be less significant when the bit period is 15 times greater than the jitter variance and becomes more significant when the signal-to-noise ratio is greater than 20 dB. Due to a good bit error rate (BER) performance (BER ≈ 10⁻²⁰at SNR= 21 dB), the DPSK modulation format has a potential application for a high-bit-rate and low-noise soliton communication system.     

Non-Gaussian statistics of soliton timing jitter induced by amplifier noise

Based on first-order perturbation theory of the soliton, the Gordon-Haus timing jitter induced by amplifier noise is found to be non-Gaussian distributed. Both frequency and timing jitter have larger tail probabilities than Gaussian distribution given by the linearized perturbation theory. The timing jitter has a larger discrepancy from Gaussian distribution than does the frequency jitter.     

Dependence of Gordon-Haus timing jitter on the ratio of the forward and backward pump powers

The Gordon-Haus timing jitter of optical pulses in dispersion-managed communication systems with distributed amplification is studied. The jitter penalty for equal forward and backward pump powers and a pump spacing of 100 km is almost 9 dB lower than the jitter penalty for lumped amplification and an amplifier spacing of 100 km.     

Timing jitter of solitons compressed in dispersion-decreasing fibers

It is shown that timing jitter owing to the Gordon-Haus (G-H) effect of solitons that are compressed adiabatically in dispersion-decreasing fibers (DDF's) is approximately determined by total dispersion and initial conditions, which are independent of compression dynamics. As a result the established theory for G-H jitter is still applicable. Timing jitter near the levels predicted by theory is observed in pulses from a regeneratively mode-locked fiber laser compressed in a DDF.     

Analysis of Gordon-Haus jitter in a dispersion-compensated optical transmission system

We theoretically analyzed the Gordon-Haus timing jitter in a periodically dispersion-compensated optical transmission system as a result of upgrading a preinstalled uniform-dispersion system. We show that the enhanced peak power for a large dispersion difference in the period reduces the frequency shift induced by noise, and a proper setting of the receiver position further reduces the timing jitter.     

Timing-jitter reduction for a dispersion-managed soliton system: experimental evidence

We have measured the timing jitter for dispersion-managed solitons in a recirculating loop for distances up to 20,000 km. The data were obtained with modulated data, 2(7) - 1 and 2(23) - 1 pseudorandom binary sequence patterns, at 10-Gbit/s rates and with an unmodulated pulse train at 10 GHz. We have obtained good agreement with our data, using a filtered Gordon-Haus model for the timing jitter reduced by the energy enhancement of our solitons relative to solitons in a fiber with a constant dispersion equal to our map's path-average dispersion. We have also measured a bit-error rate of <10(-9) at a distance of 15,000 km.     

Effects of gordon-haus jitter on soliton transmission

The bit error rate (BER) performance of an optical soliton communication system is analyzed. Based on the jitter variance equation and the chi-square distribution for the amplified spontaneous emission noise, an analytic expression for the BER calculation is obtained. We have investigated the effects of Gordon-Haus jitter, which is due to the random phase shift of the soliton individual central wavelength induced by the amplified spontaneous emission noise of the amplifiers. Very good agreement has been obtained between our theory and the reported experimental results.     

Collisions in dispersion-managed soliton propagation

We study collisions in dispersion-managed soliton propagation for wavelength-division multiplexing application at zero net dispersion when the Gordon-Haus timing jitter is removed. We show that the collisions can lead to group-velocity changes and spectral collapse. Large channel separation ameliorates the effects. Filters prevent spectral collapse but do not affect the velocity changes.     

Long-range soliton interactions in dispersion-managed links

A numerical analysis of soliton propagation in a dispersion-compensated transmission system reveals the presence of a small dispersive-wave contribution to the propagating soliton that increases dramatically whenever the input soliton energy is detuned from its optimal value. A straightforward consequence of the dispersive-wave emission is an unexpectedly strong contribution to the long-range soliton-soliton interaction. We show that the combination of long- and short-range interactions induces soliton timing jitter that grows larger than that which arises from the Gordon-Haus effect.     

Effects of gordon-haus jitter on soliton transmission

Abstract

The bit error rate (BER) performance of an optical soliton communication system is analyzed. Based on the jitter variance equation and the chi-square distribution for the amplified spontaneous emission noise, an analytic expression for the BER calculation is obtained. We have investigated the effects of Gordon-Haus jitter, which is due to the random phase shift of the soliton individual central wavelength induced by the amplified spontaneous emission noise of the amplifiers. Very good agreement has been obtained between our theory and the reported experimental results.     

Experimental observation of stable bound solitons in a figure-eight fiber laser

Temporal bound solitons are observed experimentally in a passively mode-locked figure-eight fiber laser with a dispersion-imbalanced nonlinear optical loop mirror (DI-NOLM). Soliton interactions are suppressed by use of a spectral bandpass filter, and Gordon-Haus timing jitter is eliminated with a DI-NOLM, which removes the cw light component in the laser cavity. The bound solitons are found to be stable for several hours in the laser cavity when no external perturbation is applied.     

Electrostriction-induced acoustic effect in ultralong-distance soliton transmission systems

The electrostriction-induced acoustic effect introduces a time-dependent index evolution for the following optical pulses and results in an additional temporal shift of solitons. The acoustic effect is incorporated into the nonlinear Schr?dinger equation as a perturbative term. We investigate the evolution of timing jitter, taking into account both the Gordon-Haus and the acoustic effect contributions for a 10-Gbit/s sliding-frequency in-line-filter soliton system.     

Quantum noise limits to terabaud communications

From a general model of fiber optics, we investigate the physical limits of soliton-based terabaud communication systems. In particular we consider Raman and initial quantum noise effects which are often neglected in fiber communications. Simulations of the position diffusion in dark and bright solitons show that these effects become increasingly important at short pulse durations, even over kilometer-scale distances. We also obtain an approximate analytic theory in agreement with numerical simulations, which shows that the Raman effects exceed the Gordon-Haus jitter for sub-picosecond pulses.     

增益噪声对光孤子通信系统码率距离积的限制

在采用周期性能量补偿的全光孤子通讯系统中,比特率距离积受到孤子脉冲到达时间的Gordon-Haus效应的限制。本文讨论有损光纤中微扰对孤子群速度偏移的影响,分析集中式和分布式能量补偿方式下,增益噪声引起的孤子到达时间抖动,并由此得出系统的极限比特率距离积的大小。分析结果表明:在实际系统中,分布式能量补偿方式下系统极限比特率距离积一般要比集中式能量补偿方式下的高出一倍以上。 关键词：     

Suppression of Gordon-haus effect and interaction of dark soliton by optical phase conjugation

The optical phase conjugation is put forward for the first time to suppress the Gordon-Haus effect caused by amplifier spontaneous emission noise, and soliton interaction in the dark soliton transmission system. The simulation results show : If the conjugator is sited at proper situation, it can suppress the Gordon-Haus effect or the dark soliton interaction effectively.     

Non-Gaussian statistics of an optical soliton in the presence of amplified spontaneous emission

We apply an approach based on the Fokker-Planck equation to study the statistics of optical soliton parameters in the presence of additive noise. This rigorous method not only allows us to reproduce and justify the classical Gordon-Haus formula but also leads to new exact results.     

Control filters for repeaterless soliton transmission

The Gordon-Haus limit restricts the distance of repeaterless propagation of solitons. Recently, it was found that judicious placement of filters can extend the limit. This discovery makes soliton communications competitive with other means of long distance signal transmission. This article reviews some properties of solitons, the developments since the first proposal of Hasegawa to use solitons for long distance transmission, and the recent work on control filters.     

超导纳米线单光子探测系统的时间抖动

超导纳米线单光子探测(SNSPD)器件具有较低的时间抖动特性,可以实现低误码率的QKD和高精度的激光测距。文中对超导纳米线单光子探测系统的时间抖动进行了详细的分析和测量,分析了SNSPD系统各部分对系统抖动的贡献。使用时间相关的单光子计数技术(TCSPC)和示波器的抖动分析软件,分别测量了SNSPD系统的时间抖动,比较了两种方法的优劣。在两种测量方法下,系统总的时间抖动分别约为42ps和31ps,计算后得到单光子探测器件的抖动约为25ps。发现放大器的性能对系统时间抖动影响明显。通过使用不同放大器比较分析了测量得到的时间抖动。     

多间隙气体开关触发特性

针对触发脉冲幅值、气体压强和紫外光照射3个因素对多间隙气体开关触发特性的影响规律开展实验研究。实验结果表明:触发电压由50 kV提高到70 kV时,开关触发时延的抖动降低约40%,统计时延的抖动降低约44%,形成时延的抖动变化不大。触发电压继续升高,触发抖动降低的趋势明显减缓。开关工作气压由0.16 MPa提高到0.28 MPa,开关触发时延的抖动增大约1.6倍,统计时延和形成时延的抖动均显著增大。紫外光辐照时间增长,开关触发抖动显著减小,最佳的辐照时间为80~140 ns,开关触发时延的抖动降低约39%。紫外光辐照可以有效降低开关统计时延的抖动,对形成时延影响不大。     

Intraproduction variability in jitter measures from elderly speakers

This study examined intraproduction variability in jitter measures from elderly speakers' sustained vowel productions and tried to determine whether mean jitter levels (percent) and intraspeaker variability on jitter measures are affected significantly by the segment of the vowel selected for measurement. Twenty-eight healthy elderly men (mean age 75.6 years) and women (mean age 72.0 years) were tape recorded producing 25 repeat trials of the vowels /i/, /a/, and /u/, as steadily as possible. Jitter was analyzed from two segments of each vowel production: (a) the initial 100 cycles after 1 s of phonation, and (b) 100 cycles from the most stable-appearing portion of the production. Results indicated that the measurement point selected for jitter analysis was a significant factor both in the mean jitter level obtained and in the variability of jitter observed across repeat productions.