OPTICAL INVERTER BASED ON SATURABLE ABSORBER

摘要

PROBLEM TO BE SOLVED: To provide an optical inverter which is simple and has practical effectiveness. SOLUTION: A low-power laser 18 is divided into a first beam propagating in a first beam path 24 and a second beam propagating in a second beam path 26. A saturable absorber 28 is arranged in the first beam path and acts as an optical switch which is changed over from an opaque mode to a transparent mode at the time of receiving a light input signal. The first beam and the second beam are recoupled as light beam output by an optical coupler 30. The first beam path and the second beam path have such lengths at which the phases of the first beam and the second beam offset by 180 deg. when these beams arrive at the optical coupler. When the saturable absorber 28 is changed over to the transparent mode, the first beam and the second beam are coupled so as to weaken each other. The light output beam is then darkened and logic zero is resulted. When the saturable absorber is in the opaque mode, the first beam is blocked and the light output beam turns to the second beam, making logic 1.