强色散管理准线性传输信道内非线性效应及其抑制研究

Intra-Channel Nonlinear Effects and Their Suppression in Quasi-Linear Strongly Dispersion-Managed Transmission

通过数值求解多脉冲耦合的广义非线性薛定谔方程组,对强色散管理准线性光纤传输信道内的非线性效应进行了详细的分析与讨论。比较了不同码型、不同传输功率及不同传输码率情况下信道内四波混频(IFWM)相对于信道内互相位调制(IXPM)和自相位调制(SPM)对传输的影响程度。结果表明,高码率情况下,IFWM对传输的影响最大,SPM的影响最小;随着码率的降低,IFWM及IXPM的影响减弱,SPM的影响相对增强;在码率确定的情况下,随着传输功率的增大,IFWM增强速度最快,IXPM居中,SPM增强速度较慢。将脉冲预展宽应用于强色散管理准线性传输,表明通过大范围的脉冲预展宽可有效地抑制IFWM等信道内非线性效应。

Intra-channel nonlinear effects in quasi-linear strongly dispersion-managed transmission are analyzed in detail by numerically solving the multi-pulse coupled modified nonlinear Schrodinger equations. The influences on transmission of intra-channel four-wave mixing （IFWM）, intra-channel cross-phase modulation （IXPM）, and self-phase modulation （SPM） are compared for different bit patterns, different transmitted powers, and different bit rates. Results show that, in the case of higher bit rate, IFWM is the most important nonlinearity while SPM plays a negligible role as compared to IFWM or IXPM. As the bit rate decreases, both IFWM and IXPM decline while SPM relatively increases. For a fixed bit rate, all of the three nonlinearities increase with the imcrease in input power while IFWM has the fastest increasing rate and SPM the lowest one. We propose to apply a large pre-broadening to the input pulses for quasi-linear strongly dispersion-managed transmission and find that it can efficiently suppress intrachannel nonlinear effects such as IFWM, IXPM and SPM.