Time dependent analysis of active and passive optical bistability in semiconductors

A time-dependent theory of optical bistability is developed and applied to laser amplifiers and passive semiconductor etalons. Results of the theory show an output intensity spike in switch-up which occurs after a time delay determined largely by the carrier recombination time, and before which the transition is unstable. Although for passive etalons the spike is rather broad (of order 1 ns for parameters appropriate to GaAs at 0.85 ¿¿m or InGaAsP at 1.55 ¿¿m) and of low amplitude, for amplifiers it is roughly an order of magnitude narrower and higher in amplitude. As a consequence, it is predicted that clock speeds for semiconductor bistable switching elements will be limited to rates commensurate with the carrier recombination time, not only for switch-down operations (as already well known) but also for switch-up operations.