抑制信道间干涉的40Gb/s光码分复用系统

Suppression of Interchannel Interference Noise in 40Gb/s Optical Code Division Multiplexing System

成功演示了码片速率高达280 Gchip/s的全光编解码,编解码光栅是采用"等效相移"方法制作而成的超结构光纤布拉格光栅(SSFBG)。考虑和分析了信道间干涉,实验验证了40 Gb/s×2的光码分复用(OCDM)信号复用。引入非线性光学环镜(NOLM))来抑制信道间干涉,利用非线性光学环镜的非线性开关特性将解码输出脉冲的宽度由7.7 ps压缩至3.8 ps,并同时有效的减小了干扰噪声,进而提高系统性能。理论计算和实验结果表明了采用超结构光纤布拉格光栅和非线性光学环镜实现高效编解码的可行性。高速的全光编解码可以应用于点到点的光码分复用系统以及光标签交换网络。

The 280 G-chip/s encoding and decoding rate is experimentally demonstrated. The encoder and decoder consisting of superstructured fiber Bragg gratings （SSFBGs） are fabricated using ＂equivalent phase shift＂ method. Interchannel interference noise is also considered and evaluated, and the 40 Gb/s×2 channel signal multiplexing is illustrated. In addition, a nonlinear optical loop mirror （NOLM） within the receiver is introduced to improve the system performance under two-channel operation, which reflects low-intensity signals, and transmits the highintensity signal. The NOLM can act as a nonlinear processing element capable of reducing both the pedestal and the width of the associated code recognition pulse, and the original 7.7 ps decoded pulse is compressed to 3.8 ps. The agreement between experimental and calculated results is excellent, and the feasibility of all optical high-rate encoding and decoding using SSFBG and NOLM is verified. High speed all optical encoding and decoding can be used in point to point optical code division multiplexing （OCDM） system and optical packet-switched networks.