Techniques for efficient alignment of a semiconductor laser in a Photonic Integrated Circuit (PIC) are disclosed. In some embodiments, a photonic integrated circuit (PIC) may include a semiconductor laser that includes a laser mating surface, and a substrate that includes a substrate mating surface. A shape of the laser mating surface and a shape of the substrate mating surface may be configured to align the semiconductor laser with the substrate in three dimensions.

A gallium- and nitrogen-containing laser device including an etched facet with surface treatment to improve an optical beam is disclosed.

A continuously electronically tunable semiconductor laser has a lasing section, and first and second control sections separated from the lasing section by air gaps in a longitudinal arrangement. The longitudinal arrangement positions the lasing section between the two control sections, with the longitudinal arrangement corresponding to a lasing direction of the lasing section. The arrangement places longitudinal modes of the semiconductor laser in common with the longitudinal arrangement of the sections. Current is provided to each of the first and second control sections and the lasing section. Tuning is achieved by varying the current provided to at least one of the first control section, the second control section and the lasing section.

Unidirectionality of lasers is enhanced by forming one or more etched gaps in the laser cavity. The gaps may be provided in any segment of a laser, such as any leg of a ring laser, or in one leg of a V-shaped laser. A Brewster angle facet at the distal end of a photonic device coupled to the laser reduces back-reflection into the laser cavity. A distributed Bragg reflector is used at the output of a laser to enhance the side-mode suppression ratio of the laser.

A quantum cascade semiconductor laser includes: a semiconductor mesa having a core layer extending in a direction of a first axis, and an end face extending in a direction of a second axis intersecting the direction of the first axis, and the semiconductor mesa being disposed on a principal surface of a substrate; and a reflective layer disposed on the end face of the semiconductor mesa, the reflective layer including a first semiconductor film in contact with the core layer, the core layer having a superlattice structure, the superlattice structure including a quantum well layer and a barrier layer, and the first semiconductor film of the reflective layer having a bandgap equal to or smaller than that of the quantum well layer.

Techniques for efficient alignment of a semiconductor laser in a Photonic Integrated Circuit (PIC) are disclosed. In some embodiments, a photonic integrated circuit (PIC) may include a semiconductor laser that includes a laser mating surface, and a substrate that includes a substrate mating surface. A shape of the laser mating surface and a shape of the substrate mating surface may be configured to align the semiconductor laser with the substrate in three dimensions.

A quantum cascade semiconductor laser includes: a semiconductor mesa having a core layer extending in a direction of a first axis, and an end face extending in a direction of a second axis intersecting the direction of the first axis, and the semiconductor mesa being disposed on a principal surface of a substrate; and a reflective layer disposed on the end face of the semiconductor mesa, the reflective layer including a first semiconductor film in contact with the core layer, the core layer having a superlattice structure, the superlattice structure including a quantum well layer and a barrier layer, and the first semiconductor film of the reflective layer having a bandgap equal to or smaller than that of the quantum well layer.

Gallium and nitrogen containing optical devices operable as laser diodes are disclosed. The devices include a gallium and nitrogen containing substrate member, which may be semipolar or non-polar. The devices include a chip formed from the gallium and nitrogen substrate member. The chip has a width and a length. The devices have a cavity oriented substantially parallel to the length of the chip, a dimension of less than 120 microns characterizing the width of the chip, and a pair of etched facets configured on the cavity of the chip. The pair of etched facets includes a first facet configured at a first end of the cavity and a second facet configured at a second end of the cavity.

A sensor that senses a biometric function includes at least one transmitter configured to transmit electromagnetic radiation in an emission direction, including at least one receiver configured to receive electromagnetic radiation in a receiving direction, wherein the transmitter and the receiver are configured such that the emission direction of the transmitter is inclined away from the receiving direction of the receiver by a defined angle, wherein the angle is 1 to 60.

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.