Patent ID: 7469001

Claim:
A high-powered, mid-infrared range optically pumped semiconductor laser having very weak index guiding and a simplified layered structure comprised of: a. an undoped substrate layer transparent to optical pump source wavelengths; b. an active region layer where said mid-infrared laser light is generated and having an index of refraction approximately equal to or slightly greater than the index of refraction of said substrate; c. an undoped upper clad layer having an index of refraction approximately equal to that of said substrate, whereby said active region sandwiched between said undoped substrate and said undoped upper clad layer has very weak index guiding; d. a 0.1 to 0.2 micron thick waveguide mode isolation layer comprised of any undoped material that is approximately lattice-matched to said undoped upper clad layer and has a 0.3 to 0.7 lower index of refraction than said undoped upper clad layer; e. a heat sink bonded to said waveguide mode isolation layer, whereby very weak index guiding of said active region permits a very wide transverse dimension optical mode while limiting the optical mode's transverse dimension from reaching the physical limits of the semiconductor structure, thereby enabling a high-powered, mid-infrared optically pumped semiconductor laser.