Lenslike Grating-Outcoupled Surface Emitting Laser with Superstrate Reflector

"This proposal describes two major improvements to an existing research concept for a high-average-power surface-emitting semiconductor laser with high brightness. The existing concept is the use of a lenslike lateral waveguide with a grating in thelongitudinal direction to provide feedback for laser oscillation in second-order and outcoupling from the substrate surface in first-order. We predict that such a device, with a cavity length of about 1 cm and a lateral active width of about 100 um canprovide about 10 W of peak power. By monolithically combining 40 columns of these devices on 250 um centers, a peak power of 400 W could be obtained from a 1 cm x 1 cm chip area. A grown-in epitaxial reflecting stack will minimize loss of light caused bythe bi-directional outcoupling of the grating. Efficient transfer of heat from the quantum well active region is obtained by mounting the device junction-side down with uni-directional emission through the transparent, anti-reflection coated substrate.Uniform current-injection and low contact resistance will be achieved by direct metalization to the contact layer. Distributed contacts and narrow (compared to the width of the lens waveguide) contacts will be investigated to provide low resistance.Semiconductor lasers are by far the most efficient source of laser light. However, a long term problem has been maintaining beam quality, coherence and brightness as the laser power is scaled to