A semiconductor optical device, in which a light emitting region and a modulator region are integrated, includes a first mesa disposed in the light emitting region, protruding in a direction that intersects a light propagation direction, and including an active layer, first and second buried layers disposed on the first mesa in a direction that intersects the light propagation direction and sequentially stacked in a direction in which the first mesa protrudes, a first semiconductor layer disposed on the first mesa and the second buried layer, a second mesa disposed in the modulator region and including a light absorption layer, and a third buried layer disposed on the second mesa. The first semiconductor layer and the first buried layer each have a first conductivity type. The second buried layer has a second conductivity type different from the first conductivity type, and the third buried layer is a semi-insulating semiconductor layer.

A semiconductor optical element has a mesa structure in which an active layer is embedded, and comprises a straight propagating section and a spot size converter section being such that a light confinement in the active layer is weaker than that of the straight propagating section, wherein in a same plane parallel to a layer surface of the active layer, an average value of a width of the mesa structure of the straight propagating section is smaller than a value of the width of the mesa structure at the emission facet of the spot size converter section, and at a top part of the mesa structure, an electrode is formed so that an electric current is injected in the active layer across the entire length of the straight propagating section and the spot size converter section.

A method for producing a semiconductor optical device includes the steps of bonding a semiconductor chip to an SOI substrate having a waveguide, the semiconductor chip having an optical gain and including a first cladding layer, a core layer, and a second cladding layer that contain III-V group compound semiconductors and are sequentially stacked in this order, forming a covered portion with a first insulating layer on the second cladding layer, etching partway in the thickness direction the second cladding layer exposed from the first insulating film, forming a second insulating film covering from the covered portion to a part of a remaining portion of the second cladding layer, and forming a first tapered portion that is disposed on the waveguide and tapered along the extending direction of the waveguide by etching the core layer and the second cladding layer exposed from the second insulating film.

In a method for manufacturing a nitride semiconductor light-emitting element by splitting a semiconductor layer stacked substrate including a semiconductor layer stacked body with a plurality of waveguides extending along the Y-axis to fabricate a bar-shaped substrate, and splitting the bar-shaped substrate along a lengthwise split line to fabricate an individual element, the waveguide in the individual element has different widths at one end portion and the other end portion and the center line of the waveguide is located off the center of the individual element along the X-axis, and in the semiconductor layer stacked substrate including a first element forming region and a second element forming region which are adjacent to each other along the X-axis, two lengthwise split lines sandwiching the first element forming region and two lengthwise split lines sandwiching the second element forming region are misaligned along the X-axis.

A quantum cascade laser or interband cascade laser for outputting a frequency comb. The laser's active waveguide comprises a combination of narrow and wide sections which are engineered in combination such that the laser is operable to produce lasing only in the fundamental mode across the operating wavelength range, the narrow section squeezing light propagating in the waveguide to output a frequency comb via four-wave mixing. The narrow and wide sections are further engineered to reduce the waveguide's net GVD, and also to reduce the GVD variation across the operating range compared to a comparable waveguide that is of constant width, thus producing a more stable frequency comb. The proportion of the laser's full dynamic range (i.e. from threshold to the rollover current where the maximum output power is achieved) over which lasing remains in the frequency comb regime is thereby increased compared with a constant width single mode waveguide.

A method for producing a semiconductor optical device includes the steps of bonding a semiconductor chip to an SOI substrate having a waveguide, the semiconductor chip having an optical gain and including a first cladding layer, a core layer, and a second cladding layer that contain III-V group compound semiconductors and are sequentially stacked in this order, forming a covered portion with a first insulating layer on the second cladding layer, etching partway in the thickness direction the second cladding layer exposed from the first insulating film, forming a second insulating film covering from the covered portion to a part of a remaining portion of the second cladding layer, and forming a first tapered portion that is disposed on the waveguide and tapered along the extending direction of the waveguide by etching the core layer and the second cladding layer exposed from the second insulating film.

An optical semiconductor device includes a semiconductor multilayer structure, an active region interposed between a first facet on a light emitting side and a second facet opposing to the first facet, and a first electrode layer provided on a top of the semiconductor multilayer structure and a second electrode layer provided on a bottom of the semiconductor multilayer structure; and an electrical connection region connected to at least one of the first electrode layer and the second electrode layer of the optical semiconductor device and used for injecting a current to the active region, and α>β and β>0 are satisfied where α is the contact area included in a half region on the first facet side in a top area of the optical semiconductor device and β is the contact area included in a half region on the second facet side.

A master oscillator power amplifier comprises a semiconductor laser formed on a substrate and configured to output an optical signal, and a semiconductor optical amplifier (SOA) formed on the substrate. The SOA comprises an optical waveguide having an optically active region, wherein the optical waveguide is configured to expand a mode size of the optical signal along at least two dimensions.

A semiconductor optical device includes a substrate containing silicon, and a semiconductor element bonded to the substrate, the semiconductor element being formed of a compound semiconductor and having an optical gain. The substrate includes a waveguide and a first region connected to the waveguide in an extension direction of the waveguide. The first region includes a plurality of recesses and a plurality of protrusions. Each of the plurality of recesses is recessed in a thickness direction of the substrate compared to a surface of the substrate to which the semiconductor element is bonded. Each of the plurality of protrusions protrudes in the thickness direction of the substrate from bottom surfaces of the plurality of recesses. The plurality of recesses and the plurality of protrusions are alternately disposed in a direction intersecting with the extension direction of the waveguide. The semiconductor element is bonded to the first region.

The present invention relates to a device for generating laser radiation.

An object of the present invention is to indicate a laser diode which simultaneously has a high degree of efficiency and a low degree of far field divergence.

The diode laser according to the invention comprises a current barrier (5), characterized in that the current barrier (5) extends along a third axis (X), wherein the current barrier (5) has at least one opening, and a first width (W1) of the opening of the current barrier (5) along the third axis (X) is smaller than a second width (W2) of the metal p-contact (8) along the third axis (X).