ABSTRACT
Switching is performed by loading and unloading a mirror that is formed with comb electrode actuators that are the most reliable among micro electro-mechanical systems (MEMS) actuators. This switch is made of an Si active layer on Si On Insulator substrate only by Reactive Ion Etching. If a high switching rate is required, switches based on Electro-Optical effect such as Pockels and Kerr effect are frequently used. Expectations for the MEMS switches increase as Wavelength Division Multiplexing spreads because the MEMS switches, particularly optical switches with a micromirror array have small wavelength dependence. The difficulty of switching, particularly, switching that uses three-dimensional mirrors, consists in the necessity of instant fixation of a preset mirror rotation angle with high accuracy unlike scanners or oscillator sensors. Grating Light Valve that uses a diffraction grating composed of six silicon (Si) nitride movable ribbons is used for switches as well as projectors.
