Thermal Problems of the CW Injection Laser

We describe the theoretical dependence of emitted light power on current in a continuously operating p-n junction laser, based on an injection laser model previously developed by the author. The analysis relates power output to threshold current, electrical resistance, thermal resistance, and external quantum efficiency of the laser, all quantities that can be independently measured or calculated for particular structures. The equations presented thus constitute a simple analytical model for both thermal design and diagnosis of operation of cw injection lasers.