Wavelength selective switch with superflat passbands based on a microelectromechanical system micromirror array

We propose and experimentally demonstrate an industrial wavelength selective switch (WSS) architecture based on a microelectromechanical system (MEMS) micromirror array. An anisotropic uniaxial crystal and a half-wave plate are employed as the polarization-diversity solution to reduce the polarization-dependent loss (PDL) of the WSS, and an achromatic lens composed of a positive lens and a negative lens is adopted to eliminate chromatic aberration. Experimental results show that it is possible to select and switch any wavelength channel from an input port to any output port through a two-stage beam steering process. The measured insertion loss and PDL are 4.78 and 0.5 dB, respectively. Benefiting from the customized MEMS micromirror array with a high fill factor of 96%, the 3 dB bandwidth is about 90 GHz. The results also show that the proposed WSS possesses uniform and superflat passbands for different wavelength channels. c 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)