Mode characteristics of phase-locked semiconductor laser arrays at and above threshold

A detailed eigenmode analysis of diode laser phased arrays both at and above threshold condition is presented. This analysis is based on the models developed for stripe-geometry diode lasers, in which the field equation is solved self-consistently with the carrier equation by taking into account the effect of carriers on the effective refractive index and including the stimulated emission in the carrier equation. The effect of a varying transverse confinement factor across the array is included. Numerical simulation results are obtained for threshold currents as well as laser behavior above the threshold, including the carrier density distribution, perturbed index distribution, array-mode patterns, and their associated far-field intensity distribution. Special attention has been paid to the development of the various array modes at power levels at which two array modes are oscillating simultaneously and the third one just reaches threshold.