A semiconductor device includes a substrate, a first type semiconductor structure, semiconductor columnar bodies between the substrate and the first type semiconductor structure, a first electrode and a second electrode. The first type semiconductor structure includes a first surface, a second surface opposite the first surface and away from the substrate, a first extension and a second extension respectively extending outward beyond the semiconductor columnar bodies. The first electrode and the second electrode are on the second surface of the first type semiconductor structure.

A light emitting device includes: a package including a base portion, a frame portion, and a cover portion; a light emitting element disposed on an upper surface of the base portion, surrounded by the frame portion, and configured to emit light traveling laterally; and a wavelength conversion member disposed on the base portion and including a first lateral surface on which light emitted from a light extraction surface of the light emitting element is to be incident, and an upper surface through which light is to be emitted. The frame portion includes a light shielding portion configured to shield light in a wavelength range of the light emitted from the light emitting element. The cover portion includes a light-transmissive portion configured to transmit and cause light emitted from the upper surface of the wavelength conversion member to exit to an area outside the light emitting device.

A laser module includes a gain chip, temperature sensors, a case, and a thermoelectric cooler (TEC). The gain chip emits a laser beam. One of the temperature sensors measures a first temperature of the gain chip and is encompassed by the gain chip. The other temperature sensor is adhered to the case and measures a second temperature. The TEC tunes the laser beam emitted by the gain chip to a desired wavelength by varying the first temperature of the gain chip through a set of third temperatures for various values of the second temperature. The set of third temperatures is selected from various values of the first temperature such that the laser beam emitted at the set of third temperatures is mode-hop free.

A semiconductor laser machine includes a semiconductor laser element including a first end face that emits a laser beam and a second end face that is opposite the first end face; a heat sink; and a sub-mount securing the semiconductor laser element to the heat sink. The sub-mount includes a substrate that serves as a thermal stress reliever, a solder layer joined to the semiconductor laser element, and a junction layer formed between the substrate and the solder layer. Compared with the semiconductor laser element, the substrate is extended in a rearward direction that is from the first end face toward the second end face. As for the solder layer and the junction layer, a portion of at least the solder layer is removed behind the second end face.

A semiconductor laser machine includes a semiconductor laser element including a first end face that emits a laser beam and a second end face that is opposite the first end face; a heat sink; and a sub-mount securing the semiconductor laser element to the heat sink. The sub-mount includes a substrate that serves as a thermal stress reliever, a solder layer joined to the semiconductor laser element, and a junction layer formed between the substrate and the solder layer. Compared with the semiconductor laser element, the substrate is extended in a rearward direction that is from the first end face toward the second end face. As for the solder layer and the junction layer, a portion of at least the solder layer is removed behind the second end face.

A photodetector is positioned so that imaginary lines perpendicular to an emission end surface of a first light-emitting element through first and second points, respectively, pass through the photodetector. The first and second points are two points at which an imaginary line parallel to the emission end surface through an inside of an outer edge of the first light-emitting element intersects the outer edge of the first light-emitting element in a top view. At least a part of a first wiring region is arranged in a first region between imaginary lines perpendicular to the emission end surface through third and fourth points, respectively. The third and fourth points are two points at which an imaginary line parallel to the emission end surface through an inside of an outer edge of the photodetector intersects the outer edge of the photodetector in the top view.

A photodetector is positioned so that imaginary lines perpendicular to an emission end surface of a first light-emitting element through first and second points, respectively, pass through the photodetector. The first and second points are two points at which an imaginary line parallel to the emission end surface through an inside of an outer edge of the first light-emitting element intersects the outer edge of the first light-emitting element in a top view. At least a part of a first wiring region is arranged in a first region between imaginary lines perpendicular to the emission end surface through third and fourth points, respectively. The third and fourth points are two points at which an imaginary line parallel to the emission end surface through an inside of an outer edge of the photodetector intersects the outer edge of the photodetector in the top view.

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.

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 semiconductor laser device includes: a semiconductor laser element; a lower base provided with the semiconductor laser element; an upper base that is electrically insulated from the lower base, and sandwiches the semiconductor laser element together with the lower base; a lens that allows laser light that has exited from semiconductor laser element to enter, concentrates the laser light that has entered, and allows the laser light that has been concentrated to exit; and a holder that holds the lens. The holder is connected to the upper base.