Integrated bistable optical switch - has integrated photodetector within one directional coupler output channel

摘要

The switch comprises a directional coupler with two output branches within one of which is integrated a photodetector. Spacing between the output branches is small reducing the overall geometry. Both paths (10,12) and their associated electrodes (14',14'',16',16'') are formed on a common semiconductor substrate (18). The detector (30) output is amplified (32) and fed to alternate electrodes (14',16''), the remaining electrodes being grounded. The bistable operation exhibits a hysteresis loop characteristic for power out (Ps) of one path as a function of power entering the second (Pe). The photodetector may be formed by proton implantation followed by metallising providing a reverse biassed Schottky diode. Type II to VI semiconductors may also be used. The optical switch is for use in optical communications including binary logic, discrimination, pulse forming, clipping, amplification etc.