Double Waveguide Structure For Edge-Emitting Semiconductor Laser And Method Of Forming The Same

A method of making a laser structure, comprising:

• providing a semiconductor substrate of a first conductivity type;
• forming, in sequence, a cladding layer of the first conductivity type and a waveguiding layer of the first conductivity type on the semiconductor substrate;
• forming an active region across a top surface of the first conductivity type waveguiding layer;
• forming, in sequence, a first waveguiding layer of a second, opposing conductivity type and a first cladding layer of the second, opposing conductivity type over the active region, the formed configuration defined as having a front facet and an opposing rear facet wherein upon activation an optical beam is emitted at least through the front facet;
• removing a combination of the active region, the first waveguiding layer and the first cladding layer from a portion of the formed configuration, an exposed surface formed by the removal defined as a regrowth interface;
• and
• forming, in sequence, a second waveguiding layer of the second conductivity type and a second cladding layer of the second conductivity type over the regrowth interface, selected to create a defined separation between a propagating longitudinal optical mode and the regrowth interface.

An edge-emitting semiconductor laser comprising:

• a semiconductor substrate;
• a cladding layer of a first conductivity type formed on the semiconductor substrate;
• a waveguiding layer of the first conductivity type formed on the cladding layer;
• an active region disposed over a defined region of the waveguiding layer;
• a first waveguiding layer of a second, opposing conductivity type formed over the active region;
• a first cladding layer of the second conductivity type formed over the first waveguiding layer, where defined areas of the combination of the active region, the first waveguiding layer and the first cladding layer have been removed and defining a regrowth interface along surfaces of the waveguiding layer of the first conductivity type exposed by the removal;
• a second waveguiding layer of the second conductivity type formed over the regrowth interface;
• and
• a second cladding layer of the second conductivity type formed over the second waveguiding layer of the second conductivity type, wherein the composition and thicknesses of the first waveguiding and cladding layers of the second conductivity type are selected to create a defined separation between a propagating longitudinal optical mode and the regrowth interface, including
• a first defined area of removal for the active region, the first waveguiding layer and the first cladding layer includes a recessed area along a front facet of the edge-emitting laser, the formed second guiding and cladding layers formed in the recessed area creating a non-absorbing mirror for the edge-emitting laser;
• and
• a second defined area of removal for the active region, the first waveguiding layer, and the first cladding layers including opposing lateral side areas of the edge-emitting laser in a region proximate to a current injection region, forming a central injection stripe and guiding area, the combination of the second waveguiding and cladding layers of the second conductivity type formed along the opposing lateral side areas to provide passive current confinement and lateral mode suppression.