三阶色散对色散控制孤子相互作用的影响

推导了三阶色散影响下色散控制孤子非线性相互作用的表达式,通过数值模拟分析了三阶色散对色散控制孤子非线性相互作用的影响,同时考虑了放大器自发辐射噪声对脉冲传输的影响。     

普通单模光纤中光孤子传输问题的研究

在使用普通单模光纤的光孤子传输系统中,放大器自发辐射（ASE）噪声和色散波逸出是限制光孤子传输的两个主要因素,它们将引起孤子能量科动和定时抖动,从而导致系统误码。本文分别研究了带限光滤波器对ASE噪声的抑制和非线性增益对色散波的抑制以及对孤子传输系统的稳定作用,并设计了使用普通单模光纤的光孤子传输系统。     

Impact of parametric mixing of ASE and signal on high-power festoonsystems with random dispersion variation

The effect of random dispersion variation on parametric mixing (PM) between amplified spontaneous emission (ASE) and signal has been calculated for an optically amplified nonzero dispersion-shifted fiber (NZDSF) and a single-mode fiber (SMF) festoon systems. Computer simulations were run at 2.5, 10, and 40 Gb/s with varying levels of dispersion compensation. Results of these simulations are presented in the form of relative impact on system Q. Statistics have been gathered to determine the impact of dispersion variability on the standard deviation of these Q impairments     

On the joint effects of fiber parametric gain and birefringence andtheir influence on ASE noise

Parametric gain (PG) in optical fibers may substantially enhance amplified spontaneous emission (ASE) noise, especially in long-haul amplified links. We present new results that permit to accurately characterize the effects of PG on ASE noise, as well as the interplay of PG and ASE noise with fiber dispersion in both the anomalous and normal dispersion regions. In a recent letter, we introduced the concept of a PG transfer matrix, that allows the easy evaluation of ASE noise enhancement over chains of amplified fiber spans. In the same letter we showed that the transfer matrix can be expressed in analytical closed-form when a scalar (single polarization) fiber is assumed. In this paper we extend the analysis to a more realistic two-polarization fiber model that accounts for both linear and nonlinear polarization coupling effects. We show that the new transfer matrix does not have an analytical expression, but can be easily evaluated using standard numerical algorithms. ASE noise enhancement due to PG turns out to be slightly lower in a realistic birefringent two-polarization fiber than a single-polarization fiber. An interesting result is that the single polarization model yields a convenient approximation to ASE noise enhancement, that can be evaluated analytically     

Bidirectional amplification with nonsaturable absorption and amplified spontaneous emission

A theory of bidirectional amplification is developed and applied to single-pass and double-pass laser amplifier configurations. The effects of nonsaturable absorption, longitudinal amplified spontaneous emission (ASE) gain saturation, and ASE line narrowing are included in a self-consistent formulation. An estimate of aperture scaling limitations due to transverse ASE is included. Laser performance is discussed for some conditions typical of large aperture, multikilojoule, rare gas halide (RGH) fusion amplifiers. This formulation permits tradeoff studies to be performed rapidly by altering variables spanning an eight-parameter space.     

端面反射率对单端反射半导体光放大器的影响

本文考虑了光子密度、增益谱色散、放大自发辐射噪声(ASE)、端面反射率和载流子浓度对折射率的影响,并采用细化分段法及四阶龙格-库塔法求解速率方程及光场传输方程,分析了不同端面反射率时单端反射半导体光放大器(RSOA)的动态特性。结果表明端面反射率的适当增加,可以使增益得到提高,增益恢复时间减少, ASE输出功率增加,消光比下降。理论分析为优化RSOA的动态特性具有一定的指导意义。     

放大器噪声对色散管理光孤子传输的影响

采用变分法讨论了放大器噪声对色散管理光孤子脉冲参数的影响。讨论了ASE噪声对脉冲相位、脉冲中心时间和中心频率的影响，并且对比讨论了采用密集色散管理系统和降低平均色散值后，ASE噪声对脉冲的影响，结果表明：密集色散管理孤子系统和平均色散接近于零的色散管理系统更有利于降低放大器噪声对脉冲的扰动。     

Nonlinear noise amplification in optical transmission systems with optical phase conjugation

Taking into account the influence of group-velocity dispersion (GVD) and the nonlinear Kerr effect, the nonlinear amplification of the amplified spontaneous emission (ASE) noise in fiber transmission systems using optical phase conjugation (OPC) is studied. Under a path-averaged power approximation for long-haul transmission systems, an equivalent system is developed to evaluate ASE noise amplification and accumulation in OPC systems. Combining the theoretical analysis and numerical simulations, the noise suppression effect in OPC systems is demonstrated and discussed. By using the numerical calculation method, the power variation along the system is involved in the evaluation of noise amplification. It is shown that the power variation through the system results in an imperfect compensation of the modulation instability (MI) effect, which furthermore causes the degradation of the noise suppression performance in OPC systems with anomalous dispersion.     

Effect of a Raman co-pump's RIN on the BER for signal transmission using ON-OFF keying modulation format

This paper theoretically studies the effect of the relative intensity noise (RIN), which is transferred to the signal from a Raman co-pump, on the bit-error rate (BER). We show that a given amount of the transferred RIN degrades the BER by about an order of magnitude more than does the same amount of the amplified spontaneous emission (ASE) added to the signal. We investigate how this effect depends on such parameters as the duty ratio of the signal pulses and on the amount of the ASE that has been added to the output signal along the transmission line.     

Nonlinear Evolution of Gaussian ASE Noise in ZMNL Fiber

This paper investigates the evolution of kurtosis of the input Gaussian amplified spontaneous emission (ASE) noise in a nonlinear fiber with negligible dispersion. The nonlinear Schrodinger equation (NLSE) describing propagation in optical fibers is simplified such that the fiber represents a zero memory nonlinear (ZMNL) system, and this approximation allows the development of analytical formulas for the statistical moments of the output noise. It is possible to calculate moments of all integer orders and the explicit expressions for the first four moments are given. The investigations show that the ASE noise does not preserve its Gaussian character when Kerr nonlinearity is significant. This observation proves that the common assumption of the Gaussian output ASE is not necessarily valid. Numerical simulations are provided to support the derivation. Kurtosis deviating significantly from the value typical for Gaussian noise is also an indicator that BER calculation in the coherent systems based on the assumption that ASE is Gaussian is likely to be inaccurate.     

钡蒸气中放大自发辐射与参量四波混频的竞争

研究了在双光子共振条件下，Ｂａ蒸气中放大自发辐射（ＡＳＥ）与参量四波混频（ＰＦＷＭ）的竞争过程，其机制可归结为ＡＳＥ与ＰＦＷＭ之间的干涉相消。     

OSNR Margin Brought by Nonlinear Regenerators in the Presence of PMD and Amplified Spontaneous Emission Noise

The behavior of a 2R optical regenerator in a link limited by amplified spontaneous emission (ASE) noise and polarization-mode dispersion (PMD) is investigated in detail in this paper. 2R regeneration techniques are well known for combating the accumulation ASE noise in an optical signal, but their behavior in the presence of PMD is mostly unknown. Here, we propose a general method to calculate the total outage probability in a link including a cascade of optical regenerators. Through the use of semianalytical models, we study the ability of 2R optical regenerators to combat at the same time PMD distortions and ASE noise accumulation in an optical signal, and show their interesting potential to counter independently both detrimental effects.      

Limitations in fibre Raman amplifiers imposed by Rayleighscattering of signals

A simple method of Rayleigh scattering noise calculation in fibre Raman amplifiers is proposed. Using the method, it is disclosed that the optimal Raman pump power is lower when the Rayleigh scattering of both signal and amplified spontaneous emission (ASE) are considered than when the Rayleigh scattering of ASE only is considered     

Amplified spontaneous emission in cladding-pumped L-banderbium-doped fiber amplifiers

Propagation of amplified spontaneous emission (ASE) in cladding-pumped long-wavelength-band erbium-doped fiber amplifiers (EDFAs) is analyzed numerically. Forward and backward ASE power dependence on cladding area is analyzed for both pumping directions. ASE power propagating counterdirectionally to the pump is found to experience strong dependence on the cladding area. Increasing the cladding area results in more uniform pump distribution along the EDF, preventing short-wavelength gain and ASE buildup. Quantum conversion efficiency in cladding-pumped L-band EDFAs is discussed     

基于EDFA的分布式光纤喇曼温度解调技术

为了消除掺铒光纤放大器的放大自发辐射噪声对分布式光纤温度传感器测温精度的影响,采用精确的修正公式进行温度解调是一种有效手段。通过分析掺铒光纤放大器的放大自发辐射噪声对系统产生的影响,并将计算的中间结果代入理论公式获得了修正后的温度解调公式。实验中分别采用理论公式和修正公式对温度进行分布式测量并获得了实验数据。结果表明,修正后的温度解调公式有效补偿了掺铒光纤放大器噪声引起的误差,并显著提高了系统的信噪比和测温精度;修正公式可将系统的整体测温精度提高到1℃～2℃;此外,实验中观察到多模光纤中喇曼背向自发散射同样会出现放大现象,这与单模光纤中的情形类似,且放大喇曼自发散射依然具有理想的温度效应。     

Applications of active arrayed-waveguide gratings in dynamic WDMnetworking and routing

We describe how active arrayed-waveguide gratings (AWGs) may find a diverse range of applications in future dynamic wavelength division multiplexed (WDM) networking and routing. Our initial simulations indicate that these applications include dynamic signal power and erbium-doped fiber amplifier (EDFA) gain equalization with a dynamic range of 12 dB, and interchannel amplified spontaneous emission (ASE) suppression by more than 20 dB; optical add/drop multiplexing with passband-flattened channels and suppressions of 15 dB; and dynamic dispersion compensation of up to ±300 ps/nm     

A MAP equalizer for the optical communications channel

A maximum a posteriori (MAP) equalizer is presented for optical fiber communication systems. Assuming that the span of the intersymbol interference (ISI) does not extend beyond neighboring bits-typically the case for the distortion introduced by polarization-mode dispersion (PMD)-we derive the conditional probability density function (pdf) in the electrical domain in the presence of PMD and amplified spontaneous emission (ASE)-dominated noise. Simulation results with an accurate receiver model and all-order PMD show the success of the MAP equalizer in reducing the bit error rate (BER) degradation due to PMD.     

Characterization and modeling of amplified spontaneous emission in unsaturated erbium-doped fiber amplifiers

The generation of amplified spontaneous emission (ASE) in erbium-doped fiber amplifiers (EDFAs) is characterized. A theoretical model, leading to closed-form analytical expressions for the backward and forward ASE power spectra, is developed for the unsaturated gain regime. This study shows that for the unsaturated gain regime, both power and spectral distributions of the ASE can be well described through the closed-form expressions, which require only measurable experimental parameters.<>     

双电极半导体光放大器的放大自发辐射谱和增益特性的实验研究

设计并制作了双电极多量子阱半导体光放大器（SOA）,对其放大的自发辐射(ASE)谱和增益特性进行了测试和分析。结果表明,注入电流密度分布对多电极SOA的ASE谱和增益特性有非常大的影响。通过调节注入电流密度比,ASE谱的半高全宽、峰值波长、峰值功率以及增益特性能够得到很好的调控。     

Effect of oxygen on ASE in the dye solution

The effect of oxygen on the characteristics of amplified spontaneous emission (ASE) in the dye solution has been investigated theoretically from the rate equations. When the dye solution is pumped by the laser pulses having a time duration of about 5-30 ns, the ASE radiation obtained from the dye solution is decreased by the addition of oxygen.