Optoelectronic Time-of-Flight Design and the Demonstration of an All-Optical, Stored Program, Digital Computer

The recent demonstration of an all-optical, stored program, digital computer by our group focused on high speed optoelectronic design. It was made possible by a new digital design method known as time-of-flight design. A rudimentary, but general purpose, proof of principle computer was built, which is all-optical in the sense that all signals connecting logic gates and all memory are optical in nature. LiNbO 3 directional couplers, electro-optic switches, are used to perform logic operations In addition to demonstrating stored program operation in an optoelectronic digital computer, the system demonstrated the feasibility of the new design method, which does not use any flip flops or other bistable devices for synchronization or memory. This potentially allows system clock rates of the same order as device bandwidth. This paper describes how the time-of-flight design method was motivated by the special properties of optoelectronic digital design. The basic principles of the method we employed will be discussed along with some of its potential advantages. The experimental work with digital optical circuits leading up to and including the stored program computer experiment will then be discussed. Finally, the future potential of time-of-flight design in high bandwidth optoelectronic systems will be discussed. hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh † The Center for Optoelectronic Computing Systems is sponsored in part by NSF grant number ECD 9015128 as part of the Engineering Research Centers Program, and the Colorado Advanced Technology Institute (CATI), an agency of the State of Colorado.