Abstract

Optical logic gates are realized through tire well-known phenomena of saturable gain and saturable absorption. Saturable gain occurs when the longitudinal gain of a laser is reduced by lateral injection of photons into its cavity by a control laser. The injected photons stimulate emission in a lateral mode, reducing the longitudinal gain and decreasing output power. With this effect, a laser can be turned off by a control laser, a mechanism which is useful for constructing optical OR, NOR, and NOT functions. Saturable absorption occurs when an absorbing region of a laser is optically pumped by a control laser. The injected photons increase the electron density, which decreases the absorption. With this effect, a laser can be turned on by a control laser. This property can be used to realize optical AND and NAND functions.

© 1991 Optical Society of America