Numerical simulation and optimization of microstructured high brightness broad area laser diodes

The development of broad area laser diodes towards higher output power, efficiency and brightness is essential to gain progress in almost all laser applications because those devices provide the basis for high power laser sources. To systematically improve the characteristics of high power broad area laser diodes through a design process, it is necessary to have an accurate and efficient computation model self-consistently taking into account optical, electrical and thermal properties. In this publication we present numerical techniques to compute the optical properties of the multimode beam generated by high power AlGaAs broad area laser diodes with an operating wavelength of 970 nm. This simulation considers fluctuations of the carrier and power density as well as the temperature distribution. The numerical results show an excellent agreement to measured data of conventional and microstructured high power broad area lasers. The high computation speed of the model allows optimizing microstructures inside the laser resonator with the use of a genetic optimization algorithm. We show that this design approach potentially leads to a substantial performance gain of the device. In particular degradation of the beam quality due to thermal effects at high injection currents can be controlled.