Optical bistability and monolithic logic functions based on bistable laser/light-emitting diodes

New types of bistable optical devices consisting merely of laser diodes and/or light-emitting diode and photodetectors allow one to achieve optical bistability and optical differential gain. For their novel applications, fundamental optical logic functions such as an optical AND device, inverter, and flip-flop devices are analyzed and demonstrated experimentally for the first time. The inherent simplicity of structure and operation should make it possible to establish these optical digital devices in the form of monolithic optoelectronic integration. Some schemes of their integrated logic elements are also presented and discussed for developing key elements in sophisticated optical data and image processing in the near future.