Spontaneous radiation transfer in heterojunction laser diodes

Calculations of the parameter f, which determines the proportion of the spontaneous radiation energy transmitted by the passive GaAlAs layers and absorbed outside the active layer, are presented. The value of f is required to calculate the temperature distribution inside a laser diode. It is found that the value of f for a typical GaAs–Al_0.3Ga_0.7As single-heterostructure laser diode (thickness of active layer d = 2μ and resonator length L = 400 μ) is approximately 0.335 and that for a symmetric double-heterostructure laser diode (d =0.2μ, L =400μ) is 0.671. In stripe-geometry laser diodes with a typical stripe width W = 10μ, the values of f are reduced to 0.271 and 0.658 for similar single- and double-hererostructure lasers, respectively.