中文摘要：

首先，对无阻塞的Clos（2，4，2）光网络的拓扑结构和光学实现进行了理论分析；其次，利用偏振光分束器（PBS）、相位型空间光调制器（PSLM）和反射镜设计1×2、2×2和2X4光开关。进而设计无阻塞的Clos（2，4，2）光网络，并讨论了n×m型光开光的设计原则和升级能力。最后，通过实验测试，光开关的串扰最低可以达到一24．0dB，插入损耗最低为0．54dB。理论分析和实验表明，该光开关所用器件少，具有结构简单紧凑、控制灵活方便和功能实现与信号光的偏振态无关等特点。

英文摘要：

Firstly,the structure and optical realization of non-blocking Clos（2,4,2） optical network are discussed in detail. Secondly, novel 1 × 2,2 × 2 and 2×4 optical switched are proposed with conventional polarization controlling technology by using phase spatial-light modulator（PSLM）, polarized beam split- ter（PBS） and reflective mirror,which will be used to realize the non-blocking Clos（2,4,2）optical net- work. Simultaneously, the upgrading capacity of n × m optical switch is also discussed. Finally, according to the experimental results, the minimal inter-channel crosstalk and the insertion loss are respectively -- 24.0 dB and 0.54 dB. The novel optical switches have the features of fewer optical components, compact structure, efficient performance, convenient control and function insensitive polarization of signal beam.