Increase in the power and optical damage resistance of lasers using heavily doped gallium antimonide as an active medium

A method is demonstrated to overcome saturation and to increase absolute laser output power with increasing current density without catastrophic degradation. Heavily and moderately tellurium and silicon-doped GaSb crystals were compared with pure crystals, and the increase in power of doped samples was found to arise from an increase in the density of the working levels. Analysis of output spectra shows that in doped crystals the emission results from the recombination of electrons with holes which are bound at shallow acceptor levels. Mixed doping of GaSb with a shallow donor and a shallow acceptor produces the optimum energy structure for the active region of the laser and maximizes the output parameters. The achieved radiation power densities are 1.5-2 times higher than for the previously reported electron-beam-pumped GaSb laser.