Lenslike Grating-Outcoupled Surface Emitting Laser with Superstrate Reflector

A surface-emitting semiconductor laser with a lenslike lateral layer for mode control is proposed for operation in the 975 nm wavelength range. This lens-like grating-outcoupled surface-emitting (LLGSE) laser is designed for powers of about 10 W (300microns wide and 1 cm long). Applications of LLGSEs include pumping solid state lasers used in laser radar systems, laser designators, and countermeasure systems. The LLGSE includes within the epitaxial structure a reflecting stack to minimize loss oflight towards the epitaxial (p-side) metal contact caused by the bi-directional outcoupling of the grating. Because our device is surface-emitting, the manufacturing process can have the economy of scale associated with the silicon IC industry, sincecomplete devices can be probe-tested at the wafer level. With surface-emission, the labor intensive handling required for facet coating of edge-emitting devices is eliminated, as is catastrophic optical damage (COD) and gradual facet degradation. Thisdevice has potential for extremely low cost and high electrical to optical efficiencies. The highly coherent, high brightness, single-lobe far-field provides a factor of three increase in coupling efficiency over conventional broad area diode lasers.High power monolithic arrays of LLGSEs for very high power increases reliability compared to conventional laser bar arrays.