Semiconductor laser device (1) includes lower electrode block (10) that has a first terminal hole and first and second connection holes, upper electrode block (60) that has third connection holes communicating with the respective first connection holes and a second terminal hole, heat sink (110) that has fourth connection holes communicating with the respective second connection holes, and optical component (100) attached to upper electrode block (60). The first and the second connection holes are formed on both side of a recess that is formed to house a submount on which a semiconductor laser element is disposed. Lower electrode block (10) is disposed on heat sink (110). Lower electrode block (10) and upper electrode block (60) are fastened together with first fasteners (90, 90), whereas lower electrode block (10) and heat sink (110) are fastened together with second fasteners (91, 91).

A semiconductor laser device includes first heat radiator (10) having first flow path (11) and second flow path (12) inside to allow a flow of a refrigerant and second heat radiator (20) put in contact with an upper surface of the first heat radiator. The first flow path and the second flow path are independent of each other. The second heat radiator includes an insulating member that internally has third flow path (23) communicating with first flow path (11). The semiconductor laser device further includes lower electrode block (60) disposed on a portion of an upper surface of the second heat radiator, submount (30) being made of a conductive material and being disposed on a remainder of the upper surface of second heat radiator (20), semiconductor laser element (40) disposed on an upper surface of submount (30), and upper electrode block (61) disposed such that submount (30) and semiconductor laser element (40) are clamped between the upper electrode block and second heat radiator (20). Second flow path (12) is formed below a zone for the disposition of lower electrode block (60).

A light emitting apparatus includes: a submount including a mounting face and an end face, and the end face having an upper edge apart from a front edge of the mounting face; and a quantum cascade laser disposed on the front edge and the mounting face. The quantum cascade laser includes: a laser structure having first, and second faces; a first electrode on the first face; a second electrode on the second face; and a reflecting structure on a first end face of the laser structure. The reflecting structure includes an insulating film having a first end on the first face and a second end on the second face, and a metal film having a first end on the first face, and a second end on the second face. The insulating film is disposed between the laser structure and the first end and the second end of the metal film.

A method for manufacturing a semiconductor element includes: providing a nitride semiconductor layer; performing plasma treatment to at least part of a surface of the nitride semiconductor layer in an oxygen-containing atmosphere while applying bias power; after the performing of the plasma treatment, heat treating the nitride semiconductor layer in an oxygen-containing atmosphere; forming a protective film on a region of the surface of the nitride semiconductor layer where the plasma treatment was performed; and forming an electrode in a region of the surface of the nitride semiconductor layer where the protective film was not formed.

In one embodiment, the semiconductor laser (1) comprises a semiconductor layer sequence (2) based on the material system AlInGaN with at least one active zone (22) for generating laser radiation. A heat sink (3) is thermally connected to the semiconductor layer sequence (2) and has a thermal resistance towards the semiconductor layer sequence (2). The semiconductor layer sequence (2) is divided into a plurality of emitter strips (4) and each emitter strip (4) has a width (b) of at most 0.3 mm in the direction perpendicular to a beam direction (R). The emitter strips (4) are arranged with a filling factor (FF) of less than or equal to 0.4. The filling factor (FF) is set such that laser radiation having a maximum optical output power (P) can be generated during operation.

An optical apparatus includes: an optical component opposed to and spaced apart from a light-emitting surface through which laser light is emitted; a case that houses a semiconductor laser element and the optical component and includes an introduction port for introducing gas and an exhaust port for exhausting the gas; and a flow passage section (i.e., a tubular body) including a spray port for spraying the semiconductor laser element with the gas introduced from the introduction port.

The present disclosure relates to a laser diode system. The system may have at least one laser diode emitter having a substrate, at least one laser diode supported on the substrate, and a facet which a laser beam generated by the laser diode is emitted. A cooling subsystem is included which is disposed in contact with the substrate of the laser diode emitter. The cooling subsystem includes a plurality of cooling fins forming a plurality of elongated channels for circulating a cooling fluid therethrough to cool the laser diode emitter. The cooling fluid also flows over the facet of the laser diode emitter.

A semiconductor laser device includes a heat sink, a submount, a first electrode, an insulating layer, a semiconductor laser element, a connecting portion, and a second electrode. The submount is conductive and on a first region of an upper surface of the heat sink. The first electrode is conductive and on a second region, different from the first region, of the upper surface of the heat sink. The first electrode is electrically connected either to at least part of a side surface of the submount or to an upper surface of the submount.

A coaxial transmitter optical subassembly (TOSA) including a side-by-side laser diode and monitor photodiode package, consistent with embodiments of the present disclosure, may be used in an optical transceiver for transmitting an optical signal at a channel wavelength. In an embodiment, the coaxial TOSA includes a laser sub-mount coupled to a mounting region defined by a body of the coaxial TOSA. The laser sub-mount includes a monitor photodiode disposed adjacent to a side of a laser diode such that a sensor region of the monitor photodiode is disposed within, or in close proximity to, a light cone emitted by a light emitting surface of the laser diode. The monitor photodiode is thus configured to directly receive a portion of emitted channel wavelengths from the laser diode for monitoring purposes.

A configuration of a DFB laser-based wavelength tunable laser is well known, but long resonators have difficulty in forming uniform resonators due to production variations, thereby inducing limitation in narrowing the spectral linewidth in the DFB laser-based wavelength tunable laser as well. In the semiconductor laser device of the present invention, a semiconductor laser that oscillates in a single mode and a low-loss lightwave circuit using SiO.sub.2 glass are arranged on the common substrate. The lightwave circuit is configured such that part of output light from the semiconductor laser propagates through a certain length of an optical path, and then is reflected by a reflector and is fed back to the semiconductor laser. Output light from the semiconductor laser and an input waveguide of the lightwave circuit can also be configured to be optically connected directly to each other. The present invention can provide a compact laser device with a narrowed spectral linewidth and stable wavelength controllability.