Monolithically integrated MEMS mirror array with low electrical interference in wavelength-selective switches

This paper describes the fabrication of a microelectromechanical-system (MEMS) mirror array for a wavelength-selective switch (WSS). The MEMS mirror array, in which a lot of closely spaced adjacent mirrors are electrostatically operated, consists of a MEMS mirrors and a mirror-drive electrodes. In order to reduce electrical interference, comb-shaped ground walls with a high aspect ratio of about 20 are monolithically integrated with the MEMS mirror chip. Further, U-shaped gold electroplating walls are formed in the mirror-drive electrode chip. With these walls, each MEMS mirror successfully operates with low electrical interference.