An optical semiconductor device outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The optical semiconductor device includes a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer. The optical semiconductor device further includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and the n-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The optical semiconductor device is applied to a ridge-stripe type laser.

A chip scale ultra violet laser source includes a plurality of laser elements on a substrate each including a back cavity mirror, a tapered gain medium, an outcoupler, a nonlinear crystal coupled to the outcoupler with a front facet that has a first coating that is anti-reflectivity (AR) to a fundamental wavelength of the laser element and high reflectivity (HR) to ultra violet wavelengths, and has an exit facet that has a second coating that has HR to a fundamental wavelength of the laser element and AR to the ultra violet wavelengths, a photodetector coupled to the outcoupler, a phase modulator coupled to the photodetector and coupled to the back cavity mirror, and a master laser diode on the substrate coupled to the phase modulator of each laser element. Each laser element emits an ultra violet beamlet and is frequency and phase locked to the master laser diode.

Provided is an optical transmission module in which noise is further reduced. The optical transmission module includes a first semiconductor layer having a first electrode arranged thereon, an active layer with a stripe shape formed on the first semiconductor layer, and a second semiconductor layer with a stripe shape formed on the active layer. The second semiconductor layer has a second electrode arranged thereon and includes a diffraction grating arranged along an extending direction of the active layer. The active layer includes a first portion having first stripe width, a second portion having a second stripe width smaller than the first stripe width, and a connection portion having a varying stripe width so as to connect the first portion and the second portion to each other. The diffraction grating overlaps with the first portion and does not overlap with the second portion in planar view.

A semiconductor laser includes a semiconductor layer including end faces and at least one of the end faces is configured as a light emission end face. The semiconductor layer includes a waveguide and a light window structure region. The waveguide has a first width and is extended between the end faces. The light window structure region includes an opening having a second width greater than the first width arranged along the waveguide and is formed continuously or intermittently from one to another of the end faces.

A method for manufacturing a light emitting device can include providing a substrate; forming a first active layer with a first electrical polarity; forming a light emitting region configured to emit light with a target wavelength between 200 nm and 300 nm; forming a second active layer with a second electrical polarity; forming a first electrical contact layer, optionally comprising a first optical reflector; removing a portion of the first electrical contact layer, the second active layer, the light emitting region, and the first active layer to form a plurality of mesas; and forming a second electrical contact layer. Each mesa can include a mesa width smaller than 10 times the target wavelength that confines the emitted light from the light emitting region to fewer than 10 transverse modes, or a mesa width smaller than twice a current spreading length of the light emitting device.

A semiconductor laser diode is provided. A semiconductor layer sequence has semiconductor layers applied vertically one above the other. An active layer includes an active region having a width of greater than or equal to 30 μm emitting laser radiation during operation via a radiation coupling-out surface. The radiation coupling-out surface is formed by a lateral surface of the semiconductor layer sequence and forms, with an opposite rear surface, a resonator having lateral gain-guiding in a longitudinal direction. The semiconductor layer sequence is heated in a thermal region of influence by reason of the operation. A metallization layer is in direct contact with a top side of the semiconductor layer sequence.

Single-mode distributed-feedback (DFB) lasers including single mode DFB waveguides with tapered grating structures are provided herein. Tapered grating structures provide for single mode DFB waveguides with predictable single mode operation. Uniform grating structures may provide for single mode operation, however DFB waveguides implementing uniform grating structures may operate at one of two single modes. Advantageously, DFB waveguides with tapered gratings operate with a spectrally narrow single mode at the same predictable single mode for all DFB waveguides with substantially identical specifications. Such predictability may lead to increased yield during manufacture of DFB waveguides with tapered gratings.

A semiconductor laser module (10) comprises a tapered laser diode (12) and/or a tapered amplifier diode equipped with beam shaping optics (14). The tapered laser diode and/or the tapered amplifier diode includes an emission facet (16) for emitting a laser beam (18) along a beam axis (24). The beam-shaping optics comprise a plano-convex cylindrical lens oriented so as to change divergence of the beam in the fast axis direction, the plano-convex spherical cylindrical lens having a planar surface (26) arranged facing the facet and a circular cylindrical surface (22) facing away from the facet.

Provided is a semiconductor light source element or an optical device including a semiconductor optical waveguide of a high-mesa semi-insulated embedded structure having a window structure made of the same material as an overclad layer at a light emission end, and a method for manufacturing thereof, in which an active layer at a portion of the window structure is removed, and then the same layer as the overclad layer is formed.

A semiconductor laser device includes: a substrate having a main surface; a first cladding layer with a first conductive type and a second cladding layer with a second conductive type different from the first conductive type, which are stacked over the main surface of the substrate; and a light-emitting layer that is formed between the first cladding layer and the second cladding layer, and is formed on a first surface parallel to the main surface of the substrate; the light-emitting layer has a plurality of light-emitting regions emitting laser beams in a red range; and values of peak wavelengths in an optical spectrum of the laser beams, which are emitted from the light-emitting regions, are different in accordance with the thickness of the light-emitting layer from the first surface.