III-V COMPOUND SEMICONDUCTOR MICROMACHINED ACTUATORS FOR LONG RESONATOR TUNABLE FABRY-PEROT DETECTORS

Modern telecommunication demands tunable detectors that are needed for optical demultiplexing of fibre-transmitted data. The receiver theref ore consists of a wavelength-selective detector sensitive around 1550 nm. Since detectors for this wavelength are typically fabricated on ga llium arsenide (GaAs) or indium phosphide (InP), a monolithic integrat ion with the filter provides additional functionality and reduces coup ling problems. This article presents a long-resonator Fabry-Perot filt er that has been fabricated by bulk micromachining and can be tuned by deflection of one or both of the Bragg mirrors that are realized as f loating membranes. Thermal actuation of the membrane yields mechanical sensitivities up to 153 nm mW(-1) under vacuum conditions and 13 nm m W(-1) under normal pressure. This is high enough to tune the free spec tral range with less than 5 mW. (C) 1998 Elsevier Science S.C. All rig hts reserved.