Abstract
A multimode model is proposed to simulate the mode-competition low-frequency noise in semiconductor lasers taking account of the possible mechanisms of nonlinear gain saturation. A new technique is reported to generate the Langevin noise sources that induce spontaneous-emission fluctuations in dynamics of the lasing modes. The model is applied to simulate the intensity noise in AlGaAs lasers. Agreement of the simulated noise results with the experimental measurements is found. Correlation of the noise characteristics with dynamics of the mode competition is newly introduced. The low-frequency noise is enhanced when the dynamics exhibit mode hopping or a jittering single mode, and is suppressed when the stable single-mode operation is achieved.