Gain Compression and Asymmetric Gain Due to the Bragg Grating Induced by the Standing Waves in Fabry-Perot Lasers

The Bragg grating induced by the pattern of standing waves in a Fabry-Perot laser diode is shown to give a significant contribution to nonlinear gain. We derive an analytic expression for the contribution which leads to a simple universal relation between the damping rate of relaxation oscillations, the square of the relaxation resonance frequency, and the carrier diffusion time. The effect of the standing wave grating cannot explain present experiments and this indicates that there must be additional important contributions to nonlinear gain.