Effects of resonant mode coupling on optical Characteristics of InGaN-GaN-AlGaN lasers

The phenomenon of resonant mode coupling is modeled and numerically investigated in InGaN-based multiple-quantum-well laser structures. It is shown that under resonant conditions, the internal mode coupling can lead to severe distortions of both near- and far-field characteristics. Taking into account the carrier-induced change of the modal effective index for the lasing mode, we show that the resonant internal mode coupling can result in a strongly nonlinear dependence of the modal gain on injection current, with possible region of negative differential modal gain.