This semiconductor laser device includes a semiconductor laser chip and a spatial light modulator SLM optically coupled to the semiconductor laser chip. The semiconductor laser chip LDC includes an active layer 4, a pair of cladding layers 2 and 7 sandwiching the active layer 4, a diffraction grating layer 6 optically coupled to the active layer 4, and a drive electrode E3 that is disposed between the cladding layer 2 and the spatial light modulator SLM and supplies an electric current to the active layer 4, and the drive electrode E3 is positioned within an XY plane and has a plurality of openings as viewed from a Z-axis direction and has a non-periodic structure.

Optoelectronic device undergoes selective chemical transformation like alloy compositional intermixing forming a non-transformed core region and an adjacent to it periphery where transformation has occurred. Activated by selective implantation or diffusion of impurities like Zinc or Silicon, implantation or diffusion of point defects, or laser annealing, transformation results in a change of the refractive index such that the vertical profile of the refractive index at the periphery is distinct from that in the core. Therefore the optical modes of the core are no longer orthogonal to the modes of the periphery, are optically coupled to them and exhibit lateral leakage losses to the periphery. High order transverse optical modes associated to the same vertical optical mode have higher lateral leakage losses to the periphery than the fundamental transverse optical mode, thus supporting single transverse mode operation of the device. This approach applies to single transverse mode vertical cavity surface emitting lasers, edge-emitting lasers and coherently coupled arrays of such devices.

The surface emitting laser device according to the embodiment includes a substrate, a first metal layer disposed on the substrate, a second metal layer disposed on the first metal layer, and a third metal layer disposed between the first metal layer and the second metal layer.

The first to third metal layers may include different materials, and the second metal layer may include copper (Cu).

The third metal layer may prevent diffusion of copper from the second metal layer into the first metal layer.

A two-dimensional photonic-crystal surface-emitting laser includes an active layer, a two-dimensional photonic crystal, and electrodes. The two-dimensional photonic crystal contains a plate-shaped base material arranged on one side of the active layer and different refractive index portions arranged at lattice points of a predetermined lattice in the base material and having a refractive index different from that of the base material, a band edge frequency for each position in an electric current supply region, which is at least a part of the two-dimensional photonic crystal, is monotonically increased in one direction parallel to the base material. Such a two-dimensional photonic crystal occurs when the different refractive index portion has a refractive index smaller than that of the base material, a filling factor, which is a ratio of a volume occupied by the different refractive index portion in a unit lattice constituting the lattice, is monotonically increased in the one direction.

A two-dimensional photonic-crystal surface-emitting laser includes an active layer, a two-dimensional photonic crystal, and electrodes. The two-dimensional photonic crystal contains a plate-shaped base material arranged on one side of the active layer and different refractive index portions arranged at lattice points of a predetermined lattice in the base material and having a refractive index different from that of the base material, a band edge frequency for each position in an electric current supply region, which is at least a part of the two-dimensional photonic crystal, is monotonically increased in one direction parallel to the base material. Such a two-dimensional photonic crystal occurs when the different refractive index portion has a refractive index smaller than that of the base material, a filling factor, which is a ratio of a volume occupied by the different refractive index portion in a unit lattice constituting the lattice, is monotonically increased in the one direction.

A surface emitting quantum cascade laser includes an active layer, a first semiconductor layer, and first electrode. The active layer has a plurality of quantum well layers stacked therein. The active layer is capable of emitting laser light by inter-subband transition. The first semiconductor layer is provided on the active layer and having a first surface provided with a plurality of pits so as to constitute a two-dimensional lattice. The first electrode is provided on the first semiconductor layer and having a periodic opening. Each pit is asymmetric with respect to a line parallel to a side of the lattice. The laser light is emitted in a direction generally perpendicular to the active layer from a pit exposed to the opening.

A method for fabricating a surface emitting laser includes the steps of: carrying out etching of a semiconductor laminate with a mask; and stopping the etching in response to a detection signal from an end point detector in an etching apparatus. The mask has a device area including device sections and an accessary area. The device area has an aperture ratio (OPD/SC) having a first value, the aperture ratio (OPD/SC) being defined as a total area (OPD) of an opening in each device section to an area (SC) of the device section. The accessary area has an aperture ratio having a second value configured to have substantially the same value as the first value, the aperture ratio of the accessary area being defined as an area of the opening pattern in a portion having an area, which is equal to the area of the device section, in the accessary area.

According to one embodiment, a surface-emitting quantum cascade laser includes a substrate; a mesa portion of a semiconductor stacked body located on the substrate, and a reflective film located at a sidewall of the mesa portion. The mesa portion includes a light-emitting layer emitting light due to an intersubband transition of a carrier, and a photonic crystal layer including a two-dimensional diffraction grating.

According to one embodiment, a surface-emitting quantum cascade laser includes a substrate; a mesa portion of a semiconductor stacked body located on the substrate, and a reflective film located at a sidewall of the mesa portion. The mesa portion includes a light-emitting layer emitting light due to an intersubband transition of a carrier, and a photonic crystal layer including a two-dimensional diffraction grating.

A semiconductor light emitting element that can form a useful beam pattern is provided. A semiconductor laser element LD includes an active layer 4, a pair of cladding layers 2 and 7 between which the active layer 4 is interposed, and a phase modulation layer 6 optically coupled to the active layer 4. The phase modulation layer 6 includes a base layer 6A and different refractive index regions 6B that are different in refractive index from the base layer 6A. The different refractive index regions 6B desirably arranged in the phase modulation layer 6 enable emission of laser light including a dark line with no zero-order light.