MEMS variable optical attenuator with vernier latching mechanism

A microelectromechanical-systems-based moving fiber variable optical attenuator (VOA) with a Vernier latching mechanism is described in this letter. Controlled misalignment between the end-faces of two optical fibers varies the optical coupling. This is performed using a Chevron-type thermal microactuator which moves one fiber end-face with respect to the other. The moving fiber is latched in positions using a Vernier latching mechanism with 0.5-μm step resolution. A prototype VOA has been fabricated using 80-μm silicon-on-insulator. Optical power coupled between the two single-mode fibers varied from 3.72 to -44 dBm, and over this range the VOA latched in 30 stable positions. Insertion loss was measured to be 1.05 dB. In the unlatched mode, the 10%-90% and the 90%-10% response times of the system were measured to be 1.7 and 4.8 ms, respectively.