拉曼增强型自相位调制再生技术

Raman-enhanced regenerative skill based on self-phase modulation

自相位调制可用于信号脉冲的整形,可实现归零码(RZ)信号的再生。以高非线性光纤(HNLF)为介质,在高非线性光纤中实现了拉曼集总放大和信号脉冲的自相位调制。从理论上分析了同向拉曼泵浦增强信号的自相位调制,大大降低了所需的信号光强度。论证了在色散长度(LD)远大于HNLF长度(L)时由自相位调制(SPM)导致的频谱展宽,它与脉冲的啁啾无关,频谱的功率密度与脉冲的强度无关。因此在高非线性光纤之后加入偏移载波频率的带通滤波器可实现归零码信号的再生。集中拉曼放大可增强再生性能。

The all-optical regeneration technique about return-to-zero （RZ） optical data streams can be implemented by selfphase modulation （SPM）. Highly nonlinear fiber（HNLF） is the medium in which both the discrete Rarnan amplification and self-phase modulation can be implemented. Co-pumped Raman amplification has been demonstrated to enhance self-phase modulation and reduce greatly the pulse signal power which is used to SPM in HNLF. The relation between the spectral bandwidth of the pulses broadened by SPM and the chirp of the pulses is also researched in theory and so is the relation between the spectral density of the SPM-broadened spectrum and pulse intensity, the result is that they are independent when the dispersion length is very longer than the HNLF length. Thus the all-optical data regeneration can be implemented by using band-pass filter which its pass frequency ωp offset the signal frequency ω0 and spectral bandwidth △ωp. The regenerative performance can be enhanced by the discrete Raman amplification.