光码分多址(OCDMA)技术是实现未来宽带全光接入网的最佳技术之一。提出了一种基于超结构光纤光栅(SSFBG)的光码分多址时域相位编/解码器。编/解码器根据等效相移原理,采用Sinc函数作为采样函数,仅仅利用一块均匀的相位掩模板即实现了多个性能一致的编/解码信道,可以并行对不同波长通道的用户同时进行编/解码,既节省了成本又提高了系统容量。对该编/解码器的结构和性能进行了分析,并进行了计算机仿真。结果表明,对于使用127位Gold序列的编/解码器,各通道自相关峰瓣比(P/W)大于16.3dB,峰瓣比波动小于0.4dB,归一化自相关峰值波动小于0.04,各个编码通道取得了与纯相移编/解码器相近的性能,可用于光码分多址/波分复用(WDM)混合系统。
Optical code-division multi-access (OCDMA) is one of the most attractive techniques to realize all optical access network. A new OCDMA en-decoder based on super structure fiber Bragg grating (SSFBG) is proposed. Based on the equivalent phase shift theory, the proposed en decoder adopts Sinc function as its sampling function and needs only one phase mask plate to achieve multiple en-decoding channels with similar performance. Users with different wavelength channels can be encoded (decoded) simultaneously by the proposed multi-channel en decoder, and the capacity and compatibility of the system with wavelength division multiple (WDM) are improved. Analysis and computer simulation are made on the structure and performance of the encoder-decoder. Result shows that each channel achieves equivalent performance with the pure phase-shift en decoder, the auto correlative P/W rates of each channel is more than 16.3 dB, the fluctuation of P/W rates is less than 0.4 dB, and the fluctuation of autocorrelation peak is less than 0.04 for the endecoder of 127 bit Gold-series. This multi channel en-decoder can be used in OCDMA/WDM hybrid system.