The object is to provide a technology capable of efficiently injecting a current into a core layer of a buried waveguide. On one end side of the substrate, a buried waveguide including a core layer, a cladding layer, and a current blocking layer is disposed, both sides of the core layer in a layer-stacking direction are sandwiched by the cladding layer, and both sides of the core layer in a width direction that is perpendicular to the layer-stacking direction are sandwiched by the current blocking layer. On another end side of the substrate, a ridge waveguide including the core layer and the cladding layer is disposed, and both sides of the core layer in the layer-stacking direction are sandwiched by the cladding layer.

An optoelectronic component includes a layer structure including an active zone that generates electromagnetic radiation, wherein the active zone is arranged in a plane, the layer structure includes a top side and four side faces, the first and third side faces are arranged opposite one another, the second and fourth side faces are arranged opposite one another, a strip-type ridge structure is arranged on the top side of the layer structure, the ridge structure extends between the first side face and the third side face, the first side face constitutes an emission face for electromagnetic radiation, a first recess is introduced into the top side of the layer structure laterally alongside the ridge structure, a second recess is introduced into the first recess, and the second recess extends as far as the second side face.

A method for making a laser diode with a distributed grating reflector (RT) in a planar section of a semiconductor laser with stabilized wavelength includes providing a diode formed by a substrate (S), a first cladding layer (CL1) arranged on the substrate (S), an active layer (A) arranged on the first cladding layer (CL1) and adapted to emit a radiation, and a second cladding layer (CL2) arranged on the active layer (A), said cladding layers (CL1, CL2) being adapted to form a heterojunction to allow for efficient injection of current into the active layer (A) and optical confinement, and a contact layer. The manufacturing method provides for creating, on a first portion (ZA) of the device, a waveguide (GO) for confinement of the optical radiation and, on the remaining portion (ZP) of the device, two different gratings for light reflection and confinement. The two gratings define two different zones (R1, R2), wherein the first zone (R1) includes a grating of low order and high duty cycle, and is intended for reflection, and the second zone (R2) includes a grating of the same order, or a grating of a higher order than the previous one, and low duty cycle, and is mainly intended for light confinement. The waveguide (GO) for confining the optical radiation is implemented through a lithography and a subsequent etching, whereas the grating (RT) requires a high-resolution lithography and a shallow etching starting from a planar zone.

What is provided are: an active-layer ridge which is composed of an n-type cladding layer, an active layer, a first p-type cladding layer and a second n-type blocking layer that are stacked in this order on an n-type InP substrate, and which is formed to project from a position lower than the active layer; burying layers by which both side portions of the active-layer ridge are buried up to a position higher than the active layer; first n-type blocking layers which are each stacked on a front-surface side of each of the burying layers, to be placed on the both sides of the ridge; and a second p-type cladding layer by which an end portion of the active-layer ridge and the first n-type blocking layers are buried thereunder; wherein a current narrowing window for allowing a hole current to pass therethrough is provided in and at a center of the second n-type blocking layer placed at a top of the active-layer ridge.

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 semiconductor optical element is configured to emit or absorb light and includes a lower structure that includes a multiple quantum well layer; an upper mesa structure that is disposed on the lower structure; a current injection structure that is disposed on the upper mesa structure, when seen from an optical axis of the emitted or absorbed light, a width of a portion of the current injection structure in contact with the upper mesa structure is smaller than a width of the upper mesa structure, the portion of the current injection structure in contact with the upper mesa structure consisting of InP, and an average refractive index of the upper mesa structure is higher than a refractive index of the InP forming the current injection structure; and an insulating film covering both side surfaces of the upper mesa structure and a part of an upper surface of the upper mesa structure.

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 semiconductor laser (2) includes an n-type semiconductor substrate (1), a stack of an n-type cladding layer (4), an active layer (5), and a p-type cladding layer (6) successively stacked on the n-type semiconductor substrate (1). An optical waveguide (3) includes a non-impurity-doped core layer (9) provided on a light output side of the semiconductor laser (2) on the n-type semiconductor substrate (1) and having a larger forbidden band width than the active layer (5), and a cladding layer (10) provided on the core layer (9) and having a lower carrier concentration than the p-type cladding layer (6). The semiconductor laser (2) includes a carrier injection region (X1), and a non-carrier-injection region (X2) provided between the carrier injection region (X1) and the optical waveguide (3).

The object is to provide a technology capable of efficiently injecting a current into a core layer of a buried waveguide. On one end side of the substrate, a buried waveguide including a core layer, a cladding layer, and a current blocking layer is disposed, both sides of the core layer in a layer-stacking direction are sandwiched by the cladding layer, and both sides of the core layer in a width direction that is perpendicular to the layer-stacking direction are sandwiched by the current blocking layer. On another end side of the substrate, a ridge waveguide including the core layer and the cladding layer is disposed, and both sides of the core layer in the layer-stacking direction are sandwiched by the cladding layer.

A waveguide structure including a waveguide having a thermally controllable section, and a method of manufacturing the structure. The waveguide structure comprises a plurality of layers. The layers comprise, in order: a substrate (306), a sacrificial layer (305), a lower cladding layer (303), a waveguide core layer (302), and an upper cladding layer (301). The lower cladding layer, waveguide core layer, and upper cladding layer form the waveguide, the waveguide has a waveguide core. The waveguide structure has a continuous via (307) passing through the upper cladding layer, waveguide core layer, and lower cladding layer and running parallel to the waveguide ridge (304) along substantially the whole length of the thermally controllable section. The waveguide structure also has a thermally insulating region (308) in the sacrificial layer extending at least from the via to beyond the waveguide ridge along the whole length of the thermally controllable section. The sacrificial layer comprises a sacrificial material outside of the thermally insulating region, and a thermally insulating gap (308) or thermally insulating material separating the lower cladding layer and substrate inside the thermally insulating region. The structure is manufactured by providing a wet etch to the sacrificial layer through the via in order to remove material from at least the thermally insulating region.