提出了一种基于平行排列3×3耦合器的双环结构全光缓存器(DLOB)的级联方案,分析了单级和级联结构的缓存原理及读写方式,通过分析半导体光放大器(SOA)的噪声性能,得到光缓存器输出性能主要由读写操作阶段注入的控制光功率及SOA的工作电流决定的结论,提出了在反馈式光缓存器中实现单级多圈和多级缓存的可能性,并搭建了一个两级的缓存系统,实验验证两级级联各缓存9圈时,输出信号光的功率几乎没有减少,信噪比(SNR)下降不到4 dB。理论分析和实验都表明,级联型光缓存器能够实现从纳秒级到毫秒级的缓存,可以满足未来光包交换(OPS)发展的需要。

A double loop optical buffer (DLOB) cascaded scheme based on collinear 3×3 coupler is proposed and the buffer principle and method of reading-out or writing-in operation of single-stage and cascade structure is analysed. Through analyzing the noise characteristics of the semiconductor optical amplifier (SOA), a conclusion is achieved that the output performance is determined by the control light power and the current injected into the SOA during writing and reading. And the possibility of multiple circulations buffering in one-stage buffer unit and buffering in the cascaded units is proposed. A cascaded experimental system consisting of two buffer units was set up. The experiment demonstrated that, when the optical packets traversing in two units of the cascaded buffer exceeded 9 circles respectively, the peak-peak value of output power did not decrease compared to the input optical signals, and signal-to-noise ratio (SNR) declined by less than 4 dB. The result of theoretical analysis and experiment both prove that cascaded optical buffer can provide a buffer from nanosecond to microsecond, which would meet the demand of optical packets switch (OPS) development in the future.