Thermal resistance, gain, and antiguiding factor of GaN-based cyan laser diodes

We present a highly precise method to determine the thermal resistance and the antiguiding factor of (Al,In)GaN laser diodes. Knowing the thermal resistance, we are able to exclude thermal effects and study the charge carrier density dependence of the optical gain and the refractive index. From these properties we determine the antiguiding factor. The method is applied to 489 nm (Al,In)GaN laser diodes with a high charge carrier density in the active region. For these laser diodes we find a high antiguiding factor of 10 ± 1 at the laser wavelength. Schematic drawing of the heat transport in a Fabry–Perot‐type ridge laser diode.