Spatial coherence and thermal lensing in broad-area semiconductor lasers

Injection profiled broad-area edge-emitting semiconductor lasers demonstrate single transverse mode operation and near-diffraction-limited beam output when driven by pulsed pump current. Thermal effects arising from CW operation induce filamentary dynamics, thus degrading the beam. Transition from the stable nonthermal to the unstable CW regime is analyzed experimentally and numerically, and techniques to improve beam quality in the thermal regime, based on feedback or thermal profiling, are proposed.