Self-consistent modeling of beam instabilities in 980-nm fiber pump lasers

Emission nonlinearities such as kinks in the L-I characteristic and beam steering have often been observed in semiconductor power lasers that were designed for single-made operation, A physical model of these phenomena is presented in which they are attributed to effects of the lasing and coherent coupling of multiple lateral modes. This model has been implemented self-consistently in a finite-element scheme. Simulation results for a typical 980-nm fiber pump laser are described and are found to be in good qualitative agreement with experimental observations, This agreement includes bilateral steering: of the peak field, nonsymmetric emission held intensity in a symmetric device, nonlinearity and kinks in the L-I characteristics, and beating patterns in the back plane image.