Optical fiber switch using a draw-bridge mirror for large array of interconnects

This paper reports the design, fabrication and test of a monolithically-integrated 4 × 4 free-space optical crossconnect using microfabricated polysilicon 3D-mirror to enable light-path switching for optical communication applications. The switch consists of 16 pairs of three-dimensional movable mirrors and draw-bridge plate actuators, and four input and output fibre-optic guiding rails. The draw-bridge plates actuated by the electrostatic force drive the 3D-mirrors up and down to cut off the light beam or to let the light beam pass through. The optical crossconnect is fabricated using three-layer-polysilicon surface micromachining technology. The size of the whole structures is 5 mm × 5 mm. The maximum driving voltage is about 45V, and its resonant frequency is about 5KHz (200 μm switch time). The optical insertion loss of about 1.5 dB and the crosstalk of less than - 60dB have been obtained while using GRIN-lens to collimate the input optical signals.