波长漂移对时域相位光码分多址编解码器性能的影响

Effects of Wavelength Deviation on Performance of Temporal Phase Optical Code-Division Multiple-Access En/Decoder

光码分多址(OCDMA)系统中,编解码器的性能是影响系统整体性能的关键因素之一,而波长漂移会影响编解码的性能。在分析等效相移超结构光纤光栅(EPS-SSFBG)作为光码分多址相位编解码器的基础上,仿真研究了不同码字、不同码长、不同编码带宽、不同编码效率和不同折射率调制深度的编解码器对波长漂移的容忍度(WDT)。仿真结果表明,光源与编解码器之间的波长漂移容忍度较大;若光源脉宽相对较宽,光源的中心波长偏移编解码器的中心波长一定值时,解码输出的自相关峰旁瓣比(P/W)反而提高;不同码字、不同编码效率、不同折射率调制深度都会不同程度地影响波长漂移容忍度。

The performance of optical en/decoder is one of the key factors affecting the whole performance of optical code-division multiple-access （OCDMA） system. Wavelength deviation influences the performance of en/decoder. The wavelength-deviation-tolerance （WDT） of equivalent phase shift superstructure fiber Bragg grating （EPS- SSFBG） encoder/decoder is investigated with different optical codes, different code sizes, different encoding bandwidths, different encoding efficiencies and different refractive index modulation intensities, based on the analysis of EPS-SSFBG as OCDMA encoder/decoder. The result shows that the WDT between optical source and encoder/decoder is relatively moderate, the auto-correlation ratios of PA to the maximum wing lavel （P/W） increases when the center wavelength of source deviates from that of encoder/decoder with wide input pulse width. The WDT is influenced by different optical codes, different frequency efficiencies and different refractive index modulations.