Optical Bistability and NOR-Gate Operation In Intracavity-Coupled In-Plane and Vertical Cavity Surface Emitting Lasers

Abstract

Gain-controlled, intracavity-coupled in-plane and vertical cavity surface emitting lasers (VCSELs) fabricated from the same epitaxial material have recently been reported1-2. Earlier work on gain quenching and bistability in intracavity coupled lasers involved in-plane devices only3-5. It has been pointed out that the conditions for bistability in cross coupled lasers depend on the individual lasers' self- and cross-saturation coefficients6-7. The cross saturation terms are highest when the overlap of the two lasers' gain sections is maximized. Consequently, the hysteresis in the power output vs. power input characteristic of cross-coupled VCSEL and in-plane lasers is expected to be larger and more easily realized than that observed in cross-coupled in-plane lasers alone. We report the first observation of optical bistability in cross-coupled VCSEL and in-plane lasers, and we present an all-optical two-input NOR gate which was fabricated to demonstrate the flexibility of this switching technology.