Electrostatically actuated mechanooptical waveguide ON-OFF switch showing high extinction at a low actuation-voltage

This paper reports on an integrated mechanooptical waveguide ON-OFF switch, where an absorbing element is moved into and out of the evanescent field of the guided mode in order to achieve switching. For the electrostatically driven devices, an extinction ratio of 65 dB at an actuation voltage of 2.5 V has been achieved in a 9.5-mm-long device for a wavelength of 632.8 nm. The calculated mechanical fundamental resonance frequency is 1.95 kHz. The device design enables future vacuum sealing that will annihilate the squeeze damping which, in the present device, reduces the response time to 10 s. Full-wafer scale fabrication is enabled by using standard silicon technology, chemical mechanical polishing and aligned wafer bonding. The devices can he used for channel selection purposes in integrated optical sensor arrays.