A wavelength-selective optical switch for switching arbitrary wavelengths between optical fibers in mesh networks, using interference filters for separating optical wavelengths, and two-dimensional arrays of micromirrors for switching. Broadband switch inputs and outputs are provided for adding and dropping arbitrary wavelengths at each node of the network. A two-stage multiplexer and two-stage demultiplexer are provided to simplify the free-space demultiplexer and multiplexer. Mechanisms are provided that allows full non-blocking functionality in the presence of finite yield of the micromirror arrays.