A manufacturing method for semiconductor device comprises the steps of: forming a ridge on the surface of an InP substrate; applying a photoresist to the surface of the InP substrate so as to cover the ridge; exposing through a mask an area of the photoresist covering part of an electrode contact layer at the top of the ridge, to form a resist pattern by development; applying a shrink material so as to cover resist pattern defects occurred when forming the resist pattern; forming a crosslinked portion in the defects to repair them by reacting the shrink material with an acid remaining at the exposed interface of the resist pattern; and removing by etching an electrode contact layer exposed from the resist pattern having the repaired defects after stripping away an unreacted shrink material, thereby to obtain a desired processed shape.

An optical semiconductor element having a mesa portion includes a substrate and semiconductor layers on the substrate. The optical semiconductor element further includes a first contact electrode, a second contact electrode on the semiconductor layer, first and second lead-out wires connected to the first and second contact electrodes, respectively, and an insulating film covering at least an upper surface of the semiconductor layer and the second contact electrode. The second lead-out wire is connected to the second contact electrode in an opening of the insulating film. An outer peripheral end of the second contact electrode in at least a portion where the second contact electrode and the second lead-out wire are connected is above and outside an outer peripheral end of a connection portion with the semiconductor layer, and an inner peripheral end is above and inside an inner peripheral end of the connection portion with the semiconductor layer.

In the present disclosure, in an EADFB laser in which an SOA has been integrated, a new configuration in which deterioration of optical waveform quality is solved or mitigated while keeping characteristics that a manufacturing process can be simplified by using the same layer structure is indicated. In the optical transmitter of the present disclosure, a waveguide structure having a tapered structure in at least a part of the SOA waveguide is adopted. A width of the waveguide is changed to be reduced in an SOA region, and an amount of carrier consumption is made uniform in an optical waveguide direction. A waveguide width is continuously reduced in an optical waveguide direction in the SOA so that the optical confinement coefficient is reduced, and light power distributed in an active layer region is made constant.

A QCL may include a substrate, an emitting facet, and semiconductor layers adjacent the substrate and defining an active region. The active region may have a longitudinal axis canted at an oblique angle to the emitting facet of the substrate. The QCL may include an optical grating being adjacent the active region and configured to emit one of a CW laser output or a pulsed laser output through the emitting facet of substrate.

A semiconductor optical integrated element of the present disclosure includes: a laser diode portion which is provided on one end side above a substrate, has a first optical waveguide, and emits a laser beam; a modulator portion which is provided on another end side, has a second optical waveguide, and modulates the laser beam; a separation region provided between the laser diode portion and the modulator portion; and a pair of grooves provided on both sides along the first optical waveguide and the second optical waveguide. The second optical waveguide in the separation region and the second optical waveguide in a part on the separation region side in the modulator portion have a buried structure, and the second optical waveguide in a remaining part in the modulator portion has a high-mesa-ridge structure.

The invention relates to a process for fabricating a semiconductor diode (1) via transfer of a semiconductor stack (20) then local etching to form a semiconductor pad (30), the production of the semiconductor pad (30) comprising a plurality of sequences comprising a dry etch that leaves a residual segment (23.1; 22.1), formation of a hard-mask spacer (42.1; 43.1), then a wet etch of the residual segment (23.1; 22.1).

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.

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 QCL may include a substrate, an emitting facet, and semiconductor layers adjacent the substrate and defining an active region. The active region may have a longitudinal axis canted at an oblique angle to the emitting facet of the substrate. The QCL may include an optical grating being adjacent the active region and configured to emit one of a CW laser output or a pulsed laser output through the emitting facet of substrate.

A quantum-cascade laser element includes: a semiconductor substrate; a semiconductor laminate formed on the semiconductor substrate to include a ridge portion configured to include an active layer having a quantum-cascade structure; an embedding layer including a first portion formed on a side surface of the ridge portion, and a second portion extending from an edge portion of the first portion on a side of the semiconductor substrate along a width direction of the semiconductor substrate; a metal layer formed on a top surface of the ridge portion, on the first portion, and on the second portion; and a dielectric layer disposed between the second portion and the metal layer. The dielectric layer is formed such that a part of the second portion is exposed from the dielectric layer. The metal layer is in contact with the second portion at the part.