基于半导体光放大器(SOA)的交叉增益调制效应(XGM)，提出了几种由基本逻辑与门构成的全光组合逻辑，包括一位比较器、带控制端口的2线－1线优先编码器、2线－4线译码器、2选1选择器，介绍了它们的基本结构、工作原理和真值表。利用扩展端口可进行多个组合逻辑级联，从而实现多端口、多位全光组合逻辑，如两个2线－1线优先编码器级联可实现4线－2线信号编码。结果表明基于SOA的XGM实现全光组合逻辑，原理简单、响应速度快、易于实现，是未来光子集成的一个重要发展内容。

Some kinds of all optical combinational logics are proposed based on the cross gain modulation(XGM)effect in semiconductor optical amplifiers(SOAs). The configurations, mechanisms and the true value tables are demonstrated for the combinational logics, such as the 1-bit comparator, 2-1 prior encoder which can be used to construct a 4-2 encoder, 2-4 decoder, 2-1 selector. Using the expansion ports appropriately, a few optical logics can be cascaded to form a multi-port multi-bit logic. The SOA-XGM-based logics are of simple mechanisms, high speed, reconfiguration, easy realization. All optical logic is the most important part of the future photonics integrations.