A vertical cavity surface emitter device (e.g., VCSEL or RC-LED) containing a buried index-guiding current confinement aperture layer which is grown, and lithographically processed to define position, shape and dimension of an inner aperture. In a regrowth process, the aperture is filled with a single crystalline material from the third contact layer. The aperture provides for both current and optical confinement, while allowing for higher optical power output and improved thermal conductivity.

A semiconductor laser element that includes a semiconductor layer including a waveguide formed in an intra-layer direction of the semiconductor layer and a window region formed in a front-side end face of the waveguide, has a current-laser optical output characteristic in which, at an operating temperature of 25° C. ±3° C., a laser optical output has a maximum value at a first driving current value and the laser optical output is at most 20% of the maximum value at a second driving current value greater than the first driving current value, and is not damaged at the second driving current value.

A semiconductor optical device includes an SOI substrate having a waveguide of silicon, and at least one gain region of a group III-V compound semiconductor having an optical gain bonded to the SOI substrate. The waveguide has a bent portion and multiple linear portions extending linearly and connected to each other through the bent portion. The gain region is disposed on each of the multiple linear portions.

A semiconductor laser device is a vernier-type wavelength-tunable semiconductor laser device including an optical resonator, constituted by first and second reflective elements having reflection comb spectra in which reflection peaks are arranged on a wavelength axis in a substantially periodic manner and having mutually different periods. At least one of the first and second reflective elements has a sampled grating structure having a reflection comb spectrum in which reflection phases at the respective reflection peaks are aligned and the intensity of a reflection peak outside a set laser emission wavelength bandwidth is lower than the intensity of a reflection peak within the laser emission wavelength bandwidth.

A laser device includes a wavelength-tunable laser including plural wavelength selectors in an optical resonator; a semiconductor optical amplifier that amplifies the laser light input thereto; a light intensity variation detector that detects variation in intensity of the laser light output from the wavelength-tunable laser before the laser light is input to the semiconductor optical amplifier; a wavelength dithering generation unit that generates a resonator mode wavelength dithering to modulate a resonator mode of the resonator; a wavelength dithering feedback controller that performs, on the resonator mode wavelength dithering, feedback control based on the variation in intensity detected by the light intensity variation detector; a light intensity detector that detects an intensity of the laser light output from the semiconductor optical amplifier; and a semiconductor optical amplifier feedback controller that performs feedback control on the semiconductor optical amplifier based on the intensity detected by the light intensity detector.

A distributed feedback (DFB) laser 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 DFB laser includes a separate confinement heterostructure layer positioned between the quantum well active layer and then-type cladding layer. The DFB laser includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and then-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 DFB laser has a function to select a specific wavelength by returning a specific wavelength in the wavelength-variable laser.

A buried semiconductor optical device comprises a semiconductor substrate; a mesa-stripe portion including a multi-quantum well layer on the semiconductor substrate; a buried layer consisting of a first portion and a second portion, the first portion covering one side of the mesa-stripe portion, the second portion covering the other side of the mesa-stripe portion, and the first portion and the second portion covering a surface of the semiconductor substrate; and an electrode configured to cause an electric current to flow through the mesa-stripe portion, the buried layer comprising, from the surface of the semiconductor substrate, a first sublayer, a second sublayer, and a third sublayer, the first sublayer, the second sublayer, and the third sublayer each consisting of semi-insulating InP, the first sublayer and the second sublayer forming a pair structure, the second sublayer being located above the multi-quantum well layer from the surface of the semiconductor substrate, and the second sublayer consisting of one or more layers selected from a group of InGaAs, InAAs, InGaAAs, InGaAsP, and InAlAsP.

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.

In general, a MQW semiconductor laser chip with an electrically insulated P-side region and a process for forming the same is disclosed. The MQW semiconductor laser chip, also referred to herein as a MQW semiconductor laser or simply a semiconductor laser, includes a layer of electrically insulative material that extends along at least a portion of the sidewalls to minimize or otherwise reduce the potential for electrical shorts between P and N-sides of the same when utilizing P-side bonding techniques.

Provided is a semiconductor laser diode, including a GaAs/In P substrate and a multi-layer structure on the GaAs/InP substrate. The multi-layer structure includes a lower epitaxial region, an active region and an upper epitaxial region. The active region comprises a first active layer, an epitaxial region and a second active layer, the epitaxial region is disposed between the first active layer and the second active layer, the first active layer comprises one or more quantum well structures or one or more quantum dot structures, and the second active layer comprises one or more quantum well structures or one or more quantum dot structures. the epitaxial region further comprises a tunnel junction and at least one carrier confinement layer, at least one carrier confinement layer is disposed between the tunnel junction and the first active layer or between the tunnel junction and the second active layer such that the at least one carrier confinement layer blocks electrons or holes, and no electrons or holes are able to reach the tunnel junction.