On the importance of non-thermal far-field blooming in broad-area high-power laser diodes

High-power broad-area laser diodes often suffer from a widening of the slow-axis far-field with increasing current (lateral far-field blooming). This effect is commonly attributed to self-heating. Utilizing self-consistent electro-thermal-optical simulations, we analyze previous experimental investigations of 970 nm broad-area GaAs-based Fabry-Perot lasers and reproduce the blooming mechanism in good agreement with the measurements. The simulations reveal that a substantial part of the far field blooming is not caused by self-heating but by increasing carrier and gain non-uniformity in the quantum wells.