A 2 x 2 Mechanical Optical Switch With a Thin MEMS Mirror

This paper presents the design, fabrication, alignment and experimental tests of a 2 x 2 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 2 x 2 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.