A 2$\,\times\,$ 2 Mechanical Optical Switch With a Thin MEMS Mirror

This paper presents the design, fabrication, alignment and experimental tests of a 2times2 mechanical optical switch. The key component of the mirror device is fabricated by the MEMS process that coats both sides with an ultrathin high reflection Au/Cr film (thickness less than 1.8 microns and roughness 5.7 nm) to allow double-sided reflection. The mirror is mounted on a thin metal arm, which is switched by a mechanical relay. Compared to the 4-mirror type of single-sided reflector which is used by other 2times2 optical switches, this configuration significantly reduces the size and number of the components. The optical alignment and the component assembly can rapidly be accomplished by two stages: visual coarse alignment and automatic fine alignment. Due to the feature of an adjustable mirror positioning and orientation, insertion losses can be reduced to a very low level. Experimental results show that the insertion losses, crosstalk, switching time and long-cycle test can all meet the Bellcore 1073 specification requirements.