Radiative characteristics of an injection laser with an external resonator

A comparative study was made of the radiative characteristics of injection lasers with GaAs–Ga_xA_1–xAs one-sided heterostructures operating with external selective and nonselective resonators. It was found that selection could increase the spectral density of the radiation by a factor of 20–50 without loss of the pump power. The width of the emission spectrum in a system with a nonselective external resonator remained constant in a wide range of pump powers.