Patent ID: 8571080

Claim:
A slab-coupled optical waveguide laser (SCOWL) comprising: an upper waveguide region for guiding a laser mode, said upper waveguide region being positioned in the interior regions of the SCOWL, said upper waveguide region has a thickness greater than or equal to 0.5 μm; a lower waveguide region for guiding said laser mode, said lower waveguide region being positioned in an area underneath said upper waveguide region, said lower waveguide has a thickness greater than or equal to 3 μm, where the combined thickness of the upper waveguide region and lower waveguide region is greater or equal to 4 μm; and a quantum well active region positioned between said upper waveguide region and said lower waveguide region, said quantum well active region is positioned asymmetrically within said SCOWL such that said upper waveguide region thickness is less than said lower waveguide region thickness, said quantum well active region is arranged so etching into the SCOWL is permitted to define a ridge quantum well structure within a region of said upper waveguide region, said ridge structure lined with dielectric layers, having said quantum well active region unetched, said ridge quantum well structure permits a circular mode to exist over a defined set of current levels, an etched depth is selected permitting the quantum well active region to be unetched, the distance between the quantum well active region and the etched depth defining the amount of lateral current spreading that occurs so as to improve optical confinement factor, wherein the largest fraction of said circular mode is positioned in said lower waveguide region.