A light emitting device includes a wiring substrate, a light emitting element array that includes a first side surface and a second side surface facing each other, and a third side surface and a fourth side surface connecting the first side surface and the second side surface to each other and facing each other, the light emitting element array being provided on the wiring substrate, a driving element that is provided on the wiring substrate on the first side surface side and drives the light emitting element array, a first circuit element and a second circuit element that are provided on the wiring substrate on the second side surface side to be arranged in a direction along the second side surface, and a wiring member that is provided on the third side surface side and the fourth side surface side and extends from a top electrode of the light emitting element array toward an outside of the light emitting element array.

An array of surface-emitting lasers is provided. The array outputs high brightness in a unipolar way. The array comprises a stress-adjustment unit and a plurality of epitaxial device units. The stress-adjustment unit is used to adjust stress. The stress from a substrate is used to select a laser mode for an aperture unit. The selection of the laser mode is enhanced for the aperture unit without sacrificing driving current. Low current operation is achieved in a single mode for effectively reducing volume and further minimizing the size of the whole array to achieve high-quality laser output. An object can be scanned by the outputted laser to obtain a clear image with a high resolution. Hence, the present invention is applicable for face recognition with high recognition and high security.

The present embodiment relates to a light emission device capable of removing zero-order light from output light of an S-iPM laser. The light emission device comprises an active layer and a phase modulation layer. The phase modulation layer includes a base layer and a plurality of modified refractive index regions. In a state in which a virtual square lattice is set on the phase modulation layer, a center of gravity of each modified refractive index region is separated from a corresponding lattice point, and a rotation angle around each lattice point that decides a position of the center of gravity of each modified refractive index region is set according to a phase distribution for forming an optical image. A lattice spacing and an emission wavelength satisfy a condition of M-point oscillation in a reciprocal lattice space of the phase modulation layer. A magnitude of at least one of in-plane wavenumber vectors in four directions formed in the reciprocal lattice space and each including a wavenumber spread corresponding to an angle spread of the output light is smaller than 2π/λ.

A VCSEL includes an active region between a top distributed Bragg reflector (DBR) and a bottom DBR each having alternating GaAs and AlGaAs layers. The active region includes quantum wells (QW) confined between top and bottom GaAs-containing current-spreading layers (CSL), an aperture layer having an optical aperture and a tunnel junction layer above the QW. A GaAs intermediate layer configured to have an open top air gap is disposed over a boundary layer of the active region and the top DBR. The air gap is made wider than the optical aperture and has a height equal to one quarter of VCSEL's emission wavelength in air. The top DBR is attached to the intermediate layer by applying wafer bonding techniques. VCSEL output, the air gap, and the optical aperture are aligned on the same optical axis. The bottom DBR is epitaxially grown on a silicon or a GaAs substrate.

According to one embodiment, an optical semiconductor element includes a substrate, a light emitting layer, and a distributed Bragg reflector. The light emitting layer includes an AlGaAs multi quantum well layer. The distributed Bragg reflector is provided between the substrate and the light emitting layer. A pair of a first layer and a second layer is periodically stacked in the distributed Bragg reflector. The first layer includes Al.sub.xGa.sub.1-xAs. The second layer includes In.sub.z(Al.sub.yGa.sub.1-y).sub.1-zP. A refractive index n.sub.1 of the first layer is higher than a refractive index n.sub.2 of the second layer. The first layer has a thickness larger than λ0/(4n.sub.1) where λ0 is a center wavelength of a band on wavelength distribution of a reflectivity of the distributed Bragg reflector. The second layer has a thickness smaller than λ0/(4n.sub.2).

Stacked edge-emitting lasers having multiple active regions coupled together using tunnel junctions. The composition of each of the active regions (quantum wells and/or barriers) differs to provide a controlled different emission wavelength for each junction, when each junction is individually operated at the same fixed temperature. When the device is under operation, a thermal gradient exists across the junctions, and the emission wavelengths of each junction coincide as the different temperature for each junction causes relative wavelength shifts. Thus, the effect of temperature on the emission wavelength of the device is compensated for, producing a narrower linewidth emission.

A light emitting device includes a wiring board having a first wiring layer and a second wiring layer adjacent to the first wiring layer via an insulating layer, a laser having a cathode electrode and an anode electrode, mounted on the wiring board, and driven through low-side driving, and a capacitive element mounted on the wiring board and configured to supply a drive current to the laser. The first wiring layer includes a cathode wire connected to the cathode electrode, and an anode wire connected to the anode electrode. The second wiring layer includes a reference potential wire connected to a reference potential. The reference potential wire overlaps the anode wire. The anode wire surrounds the capacitive element.

A semiconductor laser device includes: a first semiconductor layer on a first conductivity side; a second semiconductor layer on the first conductivity side; an active layer; a third semiconductor layer on a second conductivity side different from the first conductivity side; and a fourth semiconductor layer on the second conductivity side. Eg2<Eg3 is satisfied, where Eg2 and Eg3 denote maximum values of band gap energy of the second semiconductor layer and the third semiconductor layer, respectively. The third semiconductor layer includes a first region layer in which band gap energy monotonically decreases toward the fourth semiconductor layer. N2>N3 is satisfied, where N2 denotes an impurity concentration of the second semiconductor layer, and N3 denotes an impurity concentration of the third semiconductor layer.

A light-emitting module includes a substrate, a first surface-emitting laser mounted on the substrate, the first surface-emitting laser having a first engaging portion protruded outward at an end, and a second surface-emitting laser mounted on the substrate, the second surface-emitting laser having a second engaging portion recessed inward at an end. The first surface-emitting laser and the second surface-emitting laser are adjacent to each other. The first engaging portion and the second engaging portion are engaged with each other.

A vertical cavity surface emitting laser includes a first laminate including first semiconductor layers having a first Al composition, and second semiconductor layers having a second Al composition greater than the first Al composition; a current confinement structure including a current aperture and a current blocker; a first compound semiconductor layer adjacent to the current confinement structure; and a second compound semiconductor layer adjacent to the first laminate and the first compound semiconductor layer. The first compound semiconductor layer has a first aluminum profile changing monotonously in a direction from the first laminate to the current confinement structure from a first minimum Al composition within a range greater than the first Al composition and smaller than the second Al composition to a first maximum Al composition. The second compound semiconductor layer has an Al composition greater than the first Al composition and smaller than the first maximum Al composition.