New two-mode bistability in an asymmetric absorptive multisection laser diode: theoretical analysis

A novel two-mode bistable laser diode (TMBLD) with an asymmetric cavity configuration is proposed and analyzed. It consists of a gain region, a saturable absorber region, and a set of mode-selective mirrors (or filters). These elements are arranged such that the saturable absorber acts as an intracavity loss for one mode and a bleachable absorber external to the cavity of the other mode. Both modes share the same gain medium and compete for the same gain. Bleaching of the absorber leads to a switching of the modes and possible bistability. This two-mode bistability results from the complementary processes of mode competition in the gain section and the mode-dependent effective cross section of the saturable absorber. A rate equation analysis of the device indicates that a switching time less than 200 ps and a modulation rate over 3 Gb/s should be obtainable. >