色散对DWDM通信系统光纤光栅滤波器的码率限制

Dispersion-Induced Bit-Rate Limitation of Fiber Bragg Grating Filter in DWDM Communication Systems

分析了DWDM通信系统中光纤光栅滤波器色散特性对码率的影响，计算了啁啾超高斯型光脉冲情形下光栅滤波器的码率限制。计算表明，啁啾的存在严重地恶化了色散展宽，当光栅长度为几cm、信道间距与信道带宽的比值（△／Bw）≤5时，啁啾光脉冲成为限制码率的主要因素。当（△／Bw）较大时，为减少色散的影响，对光纤光栅的长度应作限制。

Transmission dispersion of fiber Bragg grating filter is demonstrated to be much more detrimental to chirped pulses,comparing to chirp-free ones,in high bit-rate dense wavelengthdivision multiplexed (DWDM) communication systems. For chirped super-ganssian pulses,pulse dispersion broadening of FGB filter becomes a key factor in limiting the bit-rate of communication systems whem △/Bw(the ration of channel spacing to channel bandwidth)≤5 land for △/B2>5,the length of FGB filter should be as short as possible in order to reduce dispersion broadening.