Optical switch for switching between multiple main light emitters

摘要

There is disclosed an optical switch for switching between a plurality of main light emitters respectively emitting light components having wavelengths different from each other and a backup light emitter adapted to replace any of the main light emitters, a light emitter switching method for switching from one failed main light emitter to a backup light emitter by using the optical switch the above switch and a light receiver switching method for switching from one failed main light receiver to a backup light receiver by using the above.