MULTISTABILITY IN GRATING-TUNED EXTERNAL-CAVITY SEMICONDUCTOR-LASERS

In this paper, we discuss the multistable state in a semiconductor las er that has an external-cavity grating system for the first time (to t he best of our knowledge). We analyzed onset conditions and stable sol ution conditions of the multistability and bistability, and observed o pen- and closed-loop multistabilities. The properties of the multistab le loops depend upon whether the internal facet reflectivity of the la ser diode is larger or smaller than the external grating cavity reflec tivity. This phenomenon directly reflects the intrinsic properties of the coherent interactions between the internal facet and the external grating cavity in the semiconductor laser diode, We experimentally obs erved the optical pulse-width memory effect in the external grating-tu ned semiconductor lasers, Based upon this setup and results, a multist able optical logic device can be built with a carefully designed compo und cavity semiconductor laser device.