Simple design of an edge-emitting diode laser for preventing spatial multimoding via thermal lensing.

The parameters of a diode-laser structure composed of a pair of built-in high-index regions for providing stable, single-spatial-mode operation to high cw powers are numerically found. A three-dimensional numerical code has been implemented that takes into account carrier diffusion in the quantum well and thermal lensing. The laser characteristics are calculated as functions of the above-threshold drive level. Within the simulation, higher-order optical modes on a "frozen background" are computed via the Arnoldi algorithm. Then, for a 6-μm-wide low-index core and 2-3-mm-long devices, stable single-mode operation up to multiwatt-level (2-3 W) cw output power is predicted.