A semiconductor device for use in an optical application and a method for fabricating the device. The device includes: an optically passive aspect that is operable in a substantially optically passive mode; and an optically active material having a material that is operable in a substantially optically active mode, wherein the optically passive aspect is patterned to include a photonic structure with a predefined structure, and the optically active material is formed in the predefined structure so as to be substantially self-aligned in a lateral plane with the optically passive aspect.

A laser comprising: at least one wavelength selective reflector that comprises a waveguide vertically coupled to at least one photonic crystal resonator, the waveguide and photonic crystal resonator being arranged to provide wave-vector matching between at least one mode of the photonic crystal resonator and at least one mode of the waveguide; an optical gain medium for generating light for coupling into the waveguide, and a reflector at an end of the optical gain medium, the reflector and the photonic crystal resonator defining a laser cavity. Light generated by the optical gain medium is coupled into the waveguide and coupled into the photonic crystal resonator, and partially reflected back to the optical gain medium.

A quantum cascade laser has an active layer, a first and second cladding layer, and an optical guide layer. The active layer has a plurality of injection quantum well regions and a plurality of light-emitting quantum well regions. The each of the injection quantum well regions and the each of the light-emitting quantum well regions are alternatively stacked. The first and second cladding layers are provided to interpose the active layer from both sides, and have a refractive index lower than an effective refractive index of the each of the light-emitting quantum well regions. The optical guide layer is disposed to divide the active layer into two parts. The optical guide layer has a refractive index higher than the effective refractive index of the each of the light-emitting quantum well regions, and has a thickness greater than the thickness of all well layers of quantum well layers.

Provided is a laser device according to an embodiment of the inventive concept. The laser device includes: a semiconductor substrate; a germanium single crystal layer on the semiconductor substrate; and a pumping light source disposed on the germanium single crystal layer and configured to emit light toward the germanium single crystal layer, wherein the germanium single crystal layer receives the light to thereby output laser.

A method for manufacturing a GaN-based surface-emitting laser by an MOVPE includes: (a) growing a first cladding layer with a {0001} growth plane; (b) growing a guide layer on the first cladding layer; (c) forming holes which are two-dimensionally periodically arranged within the guide layer; (d) etching the guide layer by ICP-RIE using a chlorine-based gas and an argon; (e) supplying a gas containing a nitrogen to cause mass-transport, and then supplying the group-III gas for growth, whereby a first embedding layer closing openings of the holes is formed to form a photonic crystal layer; and (f) growing an active layer and a second cladding layer on the first embedding layer, The step (d) includes a step of referring to already-obtained data on a relationship of an attraction voltage and a ratio of gases in the ICP-RIE with a diameter distribution of air holes embedded, and applying the attraction voltage and the ratio to the ICP-RIE.

A method for manufacturing a GaN-based surface-emitting laser by an MOVPE includes: (a) growing a first cladding layer with a {0001} growth plane; (b) growing a guide layer on the first cladding layer; (c) forming holes which are two-dimensionally periodically arranged within the guide layer; (d) etching the guide layer by ICP-RIE using a chlorine-based gas and an argon; (e) supplying a gas containing a nitrogen to cause mass-transport, and then supplying the group-III gas for growth, whereby a first embedding layer closing openings of the holes is formed to form a photonic crystal layer; and (f) growing an active layer and a second cladding layer on the first embedding layer, The step (d) includes a step of referring to already-obtained data on a relationship of an attraction voltage and a ratio of gases in the ICP-RIE with a diameter distribution of air holes embedded, and applying the attraction voltage and the ratio to the ICP-RIE.

A laser element includes a photonic crystal layer on which laser light is incident. The photonic crystal layer includes a base layer formed of a first refractive index medium; and a plurality of different refractive index regions formed of a second refractive index medium having a refractive index different from that of the first refractive index medium and disposed in the base layer. The plurality of different refractive index regions includes a first different refractive index region of which a planar shape is an approximate circle, an approximate square, or an approximate polygon having a rotational symmetry of 90° and a first area perpendicular to a thickness direction; and a second different refractive index region having a second area perpendicular to a thickness direction.

A light-emitting device includes: a substrate; and a laminated structure provided at the substrate and having a plurality of columnar parts. The columnar part has: an n-type first semiconductor layer; a p-type second semiconductor layer; a light-emitting layer provided between the first semiconductor layer and the second semiconductor layer; and an electrode provided on a side opposite to a side of the substrate, of the laminated structure. The first semiconductor layer is provided between the light-emitting layer and the substrate. An end part on a side opposite to a side of the substrate, of the light-emitting layer, has a first facet surface. An end part on a side opposite to a side of the substrate, of the second semiconductor layer, has a second facet surface. A relation of θ2≤θ1 is satisfied, where θ1 is a taper angle of the first facet surface, and θ2 is a taper angle of the second facet surface. θ1 is 70° or smaller, and θ2 is 30° or greater.

The light-emitting element of an embodiment outputs a clear optical image while suppressing light output efficiency reduction, and includes a substrate, a light-emitting unit, and a bonding layer. The light-emitting unit has a semiconductor stack, including a phase modulation layer, between first and second electrodes. The phase modulation layer has a base layer and modified refractive index regions, and includes a first region having a size including the second electrode, and a second region. Each gravity center of the second region's modified refractive index region is arranged by an array condition. The light from the stack is a single beam, and regarding a first distance from the substrate to the stack's front surface and a second distance from the substrate to the stack's back surface, a variation amount of the first distance along a direction on the substrate is smaller than a variation amount of the second distance.

In the light emitting device, each of columnar parts includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type different from the first conductivity type, and a light emitting layer disposed between the first semiconductor layer and the second semiconductor layer, the first semiconductor layer is disposed between a substrate and the light emitting layer, a laminated structure has a third semiconductor layer of the first conductivity type disposed between the substrate and the plurality of columnar parts, a first electrode is electrically connected to the first semiconductor layer via the third semiconductor layer, a contact hole is disposed in an insulating layer at a position overlapping the first electrode when viewed from a stacking direction of the first semiconductor layer and the light emitting layer, the first wiring layer is provided to the insulating layer, and the first wiring layer is electrically connected to the first electrode via the contact hole.