Abstract

The output power of GaAs/GaAlAs lasers with a buried heterostructure wave-guide designed to guarantee single mode operation has been increased above 500 mW in continuous operation at room temperature. To achieve the high output power, "window" technology has been employed which removes the active region from the facet and minimizes losses and catastrophic damage. In addition, the narrow buried heterostructure is flared at one end, adiabatically expanding the beam near the output facet. The cleaved facets are high reflectivity/low reflectivity coated to reduce the intensity at the back side of the laser in favor of higher output power. To manage the heat load of high power operation, a 1 mm long cavity is used. The vertical structure is a conventional double heterostructure grown by metal-organic-chemical vapor deposition (MOCVD). An output power exceeding 300 mW is achieved with chips mounted junction side up on copper heat sinks. Using a diamond as a heat spreader for junction side down mounting resulted in 500 mW continuous output power at room temperature. The introduction of the flare smoothed the far field pattern and reduced its width to one half. The full width at half maximum is 18° at peak power, close to the expected value for the expanded fundamental mode of the waveguide. This work was supported by the Defense Advanced Research Projects Agency and the Naval Research Laboratory under contract N00014-88-C-2099.

© 1989 Optical Society of America