Influences of quantum noises on direct-modulated properties of 1.3-μm InGaAsP/InP laser diodes

Due to the zero dispersion point at 1.3μm in optical fibres, 1.3-μm InGaAsP/InP laser diodes have become main light sources in fibre communication systems recently. Influences of quantum noises on direct-modulated properties of single-mode 1.3-μm InGaAsP/InP laser diodes are investigated in this article. Considering the carrier and photon noises and the cross-correlation between the two noises, the power spectrum of the photon density and the signal-to-noise ratio (SNR) of the direct-modulated single-mode laser system are calculated using the linear approximation method. We find that the stochastic resonance (SR) always appears in the dependence of the SNR on the bias current density, and is strongly affected by the cross-correlation coefficient between the carrier and photon noises, the frequency of modulation signal, and the photon lifetime in the laser cavity. Hence, it is promising to use the SR mechanism to enhance the SNR of direct-modulated InGaAsP/InP laser diodes and improve the quality of optical fibre communication systems.     

MODE-COMPETITION EFFECTS OF A TWO-MODE LASER WITH MULTIPLICATIVE COLORED NOISE WITH SATURATION EFFECTS

The effect of multiplicative colored noise on mode-competition of the two-mode laser with saturation effects is studied, By means of linear stability analysis, and by considering τ as a small parameter, some significant conclusions have been obtained. In strong coupling, the effect of multiplicative colored noise on mode-competition is stronger than that of multiplicative white noise, and it is enhanced with the increase of noise strength. In weak coupling, the effect of multiplicative colored noise on mode-competition is weaker than that of multiplicative white noise, and it is decreased with the increase of coupling constants.     

染料激光色立方模型的第一通过时间分布

本文首先把Ｊｕｎｇ和Ｈａｎｇｇｉ提出的统一色噪声近似推广到多维情形，从而导出了这一近似下单模染料激光色立方模型的朗之万方程和福克－普朗克方程；得到了该模型第一通过时间分布的平均值，协方差和偏斜率的近似解析式并将其和数值模拟进行比较。     

一级近似下的双模激光随机共振

将周期信号输入双模激光,对激光光强方程中的乘法噪声项取一级近似,用线性化近似方法计算相关函数和功率谱,结果发现:信噪比随抽运噪声强度、量子噪声强度及信号频率的变化均出现随机共振.