Laser-to-fiber coupling

A semiconductor laser diode, said laser diode comprising:

• a semiconductor substrate;
• a core layer comprising an active region and a waveguide region on said substrate, said waveguide region being longitudinally-displaced from an active region, and wherein said active region comprises at least one quantum well;
• an upper cladding layer on said core layer;
• a diffraction grating comprising grating fingers extending down into said top cladding layer over at least a portion of said waveguide region;
• an integrated lens-grating wherein the lens-grating is spaced by at least one-hundred wavelengths from the diffraction grating;
• and
• a coupling block connected to said semiconductor substrate and to an optical fiber.

A method of fabricating a light-generating semiconductor structure, said structure having top and bottom surfaces, said method comprising:

• providing a semiconductor substrate;
• providing a core layer containing an active-region, and a waveguide region longitudinally-displaced from an active region, said core layer being over said substrate;
• providing a top cladding layer on said core layer;
• providing a diffraction grating on said top cladding layer over at least a portion of said waveguide region;
• providing an integrated lens-grating integrated into said diffraction grating or on said bottom surface or in a coupling block cut from a glass wafer and attached to an optical fiber, said semiconductor substrate, or both;
• and
• providing at least one grating in said coupling block, wherein the at least one grating is selected from the group consisting of:
• a resonance-grating to reflect light back to the active region, a fiber-diffraction-grating to diffract light into the fiber along the fiber axis, a diffraction-grating to diffract light into the coupler and then into the fiber, the lens-gating, and a beam-shaping grating.