Patent ID: 8331744

Claim:
An optical switch adapted to switch a light beam from m (m is a natural number) optical input port to n (n is a natural number) optical output port(s) by the unit of wavelength, said optical switch comprising: a collimator which outputs a collimated light beam by collimating the light beam from the optical input port; an optical splitter which outputs dispersed light beams by dispersing the collimated light beam; a lens which outputs focused light beams by focusing the dispersed light beams; mirrors which individually have a rotatable reflection face and which output reflected light beams to the output port(s) via said lens, said optical splitter and said collimator by individually reflecting the focused light beams; a controller which controls each angle of the reflection faces to switch ON/OFF of an optical coupling of the reflected light beams to the optical output port(s); and a monitor which monitors the reflected light beam under a condition of the optical coupling to the optical output port being in an OFF state, wherein each of said mirrors has a plurality of rotation axes, wherein said controller controls an angle of a first axis of the mirror to switch ON/OFF of the optical coupling of the reflected light beam to the optical output port, and said controller controls an angle of a second axis of the mirror to switch the reflected light beam to the optical output port, and wherein said controller includes: a driver which changes the angles of said first axis and said second axis such that a locus of the reflected light beam under the condition of the optical coupling to the optical output port being in the OFF state moves cyclically; and a supervisor which detects whether the mirror operates correctly, based on an amplitude or a frequency of variation, which is caused by an operation of the driver, in light amount of the reflected light beam which is monitored by the monitor.