A method for manufacturing a semiconductor light-emitting device includes: forming a plurality of guide grooves so as to be depressed from a surface of a semiconductor structure layer toward a semiconductor substrate and to align and extend along a direction perpendicular to an extending direction of a plurality of line electrodes; forming, in each of the plurality of guide grooves, a scribe groove so as to be depressed from a bottom surface of the guide groove toward the semiconductor substrate and to extend along an extending direction of the guide groove; and dividing a semiconductor wafer along the plurality of guide grooves. The guide groove and the scribe groove are formed to have end shapes in such a manner that inner walls thereof project toward each other in the extending direction of the scribe groove.

Structures and methods for reducing wafer bow during heteroepitaxial growth are described. Micro-trenches may be formed across a surface of a substrate and filled with polycrystalline material. Stress-relieving regions of material can be grown over the polycrystalline material in a layer of semiconductor material during heteroepitaxy.

Structures and methods for reducing wafer bow during heteroepitaxial growth are described. Micro-trenches may be formed across a surface of a substrate and filled with polycrystalline material. Stress-relieving regions of material can be grown over the polycrystalline material in a layer of semiconductor material during heteroepitaxy.

A laser module includes a substrate, a laser unit, an optical amplification unit, a high reflection layer and a low reflection layer. The laser unit is disposed on the substrate and configured to generate a laser light. The optical amplification unit is disposed on the substrate. An optical channel of the optical amplification unit is communicated with an optical channel of the laser unit. An electrode of the optical amplification unit is electrically isolated from an electrode of the laser unit. The high reflection layer is disposed on an end of the laser unit away from the optical amplification unit. The low reflection layer is disposed on an end of the optical amplification unit away from the laser unit. The laser light and a gain light are emitted to an outside of the laser module via the low reflection layer. A method for manufacturing the laser module is also provided.

A laser module includes a substrate, a laser unit, an optical amplification unit, a high reflection layer and a low reflection layer. The laser unit is disposed on the substrate and configured to generate a laser light. The optical amplification unit is disposed on the substrate. An optical channel of the optical amplification unit is communicated with an optical channel of the laser unit. An electrode of the optical amplification unit is electrically isolated from an electrode of the laser unit. The high reflection layer is disposed on an end of the laser unit away from the optical amplification unit. The low reflection layer is disposed on an end of the optical amplification unit away from the laser unit. The laser light and a gain light are emitted to an outside of the laser module via the low reflection layer. A method for manufacturing the laser module is also provided.

A quantum cascade laser is configured with a semiconductor substrate, and an active layer provided on a first surface of the substrate and having a cascade structure in the form of a multistage lamination of unit laminate structures each of which includes an emission layer and an injection layer. The active layer is configured to be capable of generating first pump light of a frequency .sub.1 and second pump light of a frequency .sub.2 by intersubband emission transitions of electrons, and to generate output light of a difference frequency by difference frequency generation from the first pump light and the second pump light. Grooves respectively formed in a direction intersecting with a resonating direction in a laser cavity structure are provided on a second surface opposite to the first surface of the substrate.

A quantum cascade laser is configured with a semiconductor substrate, and an active layer provided on a first surface of the substrate and having a cascade structure in the form of a multistage lamination of unit laminate structures each of which includes an emission layer and an injection layer. The active layer is configured to be capable of generating first pump light of a frequency .sub.1 and second pump light of a frequency .sub.2 by intersubband emission transitions of electrons, and to generate output light of a difference frequency by difference frequency generation from the first pump light and the second pump light. Grooves respectively formed in a direction intersecting with a resonating direction in a laser cavity structure are provided on a second surface opposite to the first surface of the substrate.

A semiconductor laser element includes a substrate and a semiconductor stacked structure that is provided on one face of the substrate. The semiconductor stacked structure includes an optical waveguide. A pair of first recesses are provided in an other face of the substrate, the pair of first recesses extending in the resonator length direction. Both end portions of each of the pair of first recesses are located in positions recessed from end faces of the semiconductor stacked structure. Second recesses are provided in the semiconductor stacked structure, the second recesses extending from the end faces of the semiconductor stacked structure in the resonator length direction. In a top view, the second recesses are provided on both sides of the optical waveguide, and are each provided between a corresponding one of the pair of first recesses and the optical waveguide.

A semiconductor laser element includes a substrate and a semiconductor stacked structure that is provided on one face of the substrate. The semiconductor stacked structure includes an optical waveguide. A pair of first recesses are provided in an other face of the substrate, the pair of first recesses extending in the resonator length direction. Both end portions of each of the pair of first recesses are located in positions recessed from end faces of the semiconductor stacked structure. Second recesses are provided in the semiconductor stacked structure, the second recesses extending from the end faces of the semiconductor stacked structure in the resonator length direction. In a top view, the second recesses are provided on both sides of the optical waveguide, and are each provided between a corresponding one of the pair of first recesses and the optical waveguide.

Provided is an optical semiconductor device which has long-term reliability since a threshold current is small, and a relaxation oscillation frequency is high. An optical semiconductor device includes an InP semiconductor substrate, a lower mesa structure that is disposed above the InP semiconductor substrate, and includes a multiple quantum well layer, an upper mesa structure that is disposed on the lower mesa structure, and includes a cladding layer, a buried semiconductor layer that buries both side surfaces of the lower mesa structure, and an insulating film that covers both side surfaces of the upper mesa structure by being in contact with both side surfaces of the upper mesa structure, in which the lower mesa structure includes a first semiconductor layer, above the multiple quantum well layer, and the upper mesa structure includes a second semiconductor layer which is different from the cladding layer in composition, below the cladding layer.