硅基液晶(LCoS)是一种新型可编程的衍射光学元件，已广泛应用于光学显示、通信与存储等领域。研究了LCoS 的光束衍射特性，并将其作为波长切换器应用于1×N 型波长选择开关中，成功实现了输入与任意输出端口之间的波长切换。利用光学标量衍射理论计算得到LCoS 上1 级光强分布及衍射效率与各物理参量的关系。结果表明：单位周期内相位阶数不低于10 时，衍射损耗可稳定控制在5 dB 内。在此基础上，巧妙设计了基于LCoS 的1×N 型波长选择开关(WSS)，利用LCoS 相位光栅设置的高度灵活性实现输出通道间隔的灵活可调。通道之间低串扰且独立可控。实验测得WSS 系统损耗为10 dB~14 dB。

Liquid crystal on silicon (LCoS) is a novel programmable diffraction optical element, which has been widely used in optical display, communication and storage etc. The diffraction of LCoS is analyzed and applied into 1 × N wavelength selective switch (WSS) as a wavelength selector, which has succeeded in switching the input wavelength to any output port. Based on the optical scale diffraction theory, the 1st diffraction distribution and efficiency of LCoS are discussed. The results show that the diffraction loss of LCoS is stable and lower than 5 dB when the grating phase order is greater than 10 pixels. Further, an LCoS-based 1 × N WSS is designed and the flexible modulation of channel space is realized. The WSS crosstalk is low and each output can be controlled independently. The total system loss is around 10 dB~14 dB.