Single-and dual-filament self-sustained oscillations in d.h.injection lasers

We analyse a theoretical model of self-sustained oscillations in D.H. injection lasers, where a single or two filaments feed on two distinct carrier reservoirs, and consider the simultaneous effect of optical coupling by saturable absorption, carrier diffusion, and by spontaneous emission. We derive conditions for instability valid for any form of the gain function and specialise the results to the case of logarithmic and linear gain. Numerical results are presented showing trajectories in the phase plane of the carrier densities as well as the time evolution of carrier and photon densities.