Integrated optical half adder circuit.

An integrated optical half adder circuit was fabricated on LiNbO(3) substrate. The circuit is composed of several elementary logic gates. Interaction between guided light beams was achieved by utilizing LiNbO(3) electrooptic modulators, which operate by changing the cutoff condition of the lowest order guided mode in an outdiffused LiNbO(3) channel waveguide, and CdS photodetectors. Light signals were injected into an array of channel waveguides by end-fire coupling from an array of four single mode optical fibers arranged in preferentially etched V-grooves in silicon.