MEMS tunable silicon nano-wire air-gap coupling for coupler switch and interferometer

Air-gap silicon waveguide couplers are studied for tunable optical telecommunication devices. Air-gap of coupler can be modulated by a MEMS actuator to vary the coupling efficiency, and the position of coupler can also be shifted by the actuator for varying the optical path length. We study the characteristics of the air-gap coupler theoretically and experimentally. Fabricated MEMS actuators are so small to be embedded in the vicinity of silicon nano-wire waveguides. The optical characteristics of the air-gap coupler are investigated as functions of air-gap and lateral displacement. These mechanisms are useful for a coupler switch and an interferometer, and they are experimentally studied.