WDM系统中ASE噪声的二阶色散效应

Quadratic dispersion effect of amplified self-emission(ASE) noise in WDM systems

讨论了采用小信号分析法研究脉冲波在色散、非线性光纤中的传输时,放大的自发辐射(ASE)噪声作为功率调制项加入脉冲波的传输方程后所产生的效应。ASE噪声不仅被互相位调制不稳定增益所放大,还受二阶色散成分的影响。其传输函数为cos(1/2β2dzω2),这一函数不能通过色散补偿来消除,会削弱ASE噪声的影响。鉴于此,ASE噪声可以通过合适的选择放大器间的距离和信号波长来消除,从而放大器间的距离也可以相应地增加约20km。

While ASE noise is added as the amplitude modulation item, the pulse transmissions in dispersion and nonlinear fibers can be analyzed by the small signal analysis method. ASE noise is not only amplified by the cross-phase modulation instability gain, but also affected by the quadratic dispersion component. The transfer function is cos（1/2β2dzω^2）which can not be compensated by dispersion and makes the ASE noise reduce. Therefore, the ASE noise can be eliminated by the suitable choices of amplifier spacing and signal wavelength, and thus the amplifier spacing can also be enlarged.