Optical bistability in twin-stripe lasers

The paper reports optical and current-triggered bistable switching of twin-stripe lasers. External light sources have been used to trigger the bistable switching directly, and the twin-stripe laser has been used in optical flip-flop configuration. The mechanisms causing the observed bistable switching have been investigated. The switching is believed to be associated with a change in the dominant waveguiding mechanism from self focusing to gain guiding, as the mode is observed to switch from a central self-focused mode to a gain-guided one crossing from one side of the laser at one facet to the other side at the opposite facet. The direction in which the crossing occurs is critically dependent on bias and may allow a tristable device to be developed. A simple theoretical model is reported to confirm the above hypotheses.