半导体光放大器的光-光互作用及其应用

半导体光放大器（SOA）中的非线性系数约为普通光纤的10^9，为光子晶体光纤的10^7，而且有4种光-光互作用，即交叉增益调制（XGM）、交叉相位调制（XPM）、交叉偏振调制（XSM）及四波混频（FWM），可以灵活地组成各种光信号处理器件，如波长变换器、全光触发器、全光逻辑、全光时钟恢复、全光缓存器……等，正成为整个光信号处理的基础。文章介绍了它们的原理和简单应用。

Interaction of two light beams in semiconductor optical amplification and applications in all-optical signal processing

In semiconductor optical amplification (SOA) the nonlinearity coefficient is about 109 times greater than that in commercial optical fiber and 107 times that in photonic crystals. There are four interactions involved with two beams of light: cross gain modulation, cross phase modulation, cross state-of-polarization modulation, and four-wave maxing. Thus, SOA can be flexibly incorporated into many kinds of all-optical processing devices, such as wavelength converters, all-optical flip-flop switches, logic devices, clock recovery, buffers, and so forth. Indeed, it is now becoming the cornerstone of optical signal processing. The principle of SOA and its basic applications are reviewed.