Abstract: An apparatus and method for high speed phase modulation of optical beam with reduced optical loss. In one embodiment, an apparatus includes a first region of an optical waveguide disposed in semiconductor material. The first region has a first conductivity type. The apparatus also includes a second region of the optical waveguide disposed in the semiconductor material. The second region has a second conductivity type opposite to the first conductivity type. A first contact is included in the apparatus and is coupled to the optical waveguide at a first location in the first region outside an optical path of an optical beam to be directed through the optical waveguide. The apparatus also includes a first higher doped region included in the first region and coupled to the first contact at the first location to improve an electrical coupling between the first contact and the optical waveguide. The first higher doped region has a higher doping concentration than a doping concentration within the optical path.

Abstract: A nitride-based semiconductor laser device capable of attaining stabilization of a laser beam and inhibiting a threshold current and an operating current from increase is provided. This nitride-based semiconductor laser device comprises a substrate consisting of either a nitride-based semiconductor doped with an impurity or a boride-based material, an n-type cladding layer formed on the substrate, an active layer consisting of a nitride-based semiconductor formed on the n-type cladding layer, a p-type cladding layer formed on the active layer and a light guide layer formed only between the active layer and the p-type cladding layer in the interspaces between the active layer and the n- and p-type cladding layers.

Abstract: In the fields of semiconductor laser devices made of nitride semiconductor layers, the present invention provides a semiconductor laser device having higher output and longer lifetime characteristics and a manufacturing method thereof. The semiconductor laser device according to the present invention includes a resonator that has: the first cladding layer which is made of n-type GaN or n-type AlGaN; an active layer which is made of an AlGaInN multiple quantum well and positioned above the first cladding layer; the second cladding layer which is made of p-type or undoped GaN, or p-type or undoped AlGaN and positioned above the active layer; and the third cladding layer which is made of p-type GaN or p-type AlGaN and positioned above the second cladding layer. The resonator also has an ion implanted part at an end part of the resonator.

Abstract: Embodiments provide a vertical external cavity surface emitting laser (VECSEL) that may provide a uniform current density in an active layer using a double current injecting channel. The surface emitting laser device may include a double channel current injection structure for uniformly applying current to an active layer, wherein the double channel current injection structure may include: a first current injection channel, which may allow current to be injected toward a central portion of an aperture, which may be a light beam output region formed in the active layer, and may have a smaller diameter than the aperture: and a second current injection channel, which may allow current to be injected toward an edge of the aperture and may be located around the aperture.

Abstract: A semiconductor laser device has a pair of cladding layers with an active layer interposed therebetween. At least one of the cladding layers is of the same composition through the entire region of the cladding layer, excluding a dopant in the cladding layer, and has a stripe portion different in conductivity type from adjacent portions.

Abstract: A surface emitting laser device is disclosed that is able to selectively add a sufficiently large loss to a high order transverse mode so as to efficiently suppress a high order transverse mode oscillation and to oscillate at high output in a single fundamental transverse mode. The surface emitting laser device includes a first resonance region that includes an active layer and spacer layers, two distributed Bragg reflectors that sandwich the resonance region, and a current confinement structure that defines a current injection region for the active layer. At least one of the distributed Bragg reflectors includes a second resonance region arranged in the current injection region excluding a predetermined region surrounding a center of the current injection region.

Abstract: A DFB semiconductor laser device including an n-type semiconductor substrate and a layer structure, overlying the semiconductor substrate, including an active layer, a compound semiconductor layer constituting a diffraction grating and overlying the active layer, and an embedding layer embedding the diffraction grating, wherein said at least one of the compound semiconductor layer and the embedding layer has a carrier density of 7×1017 to 2×1018 cm?3.

Abstract: A device and method for hetero laser and light-emission of high polarization radiation. Previous light emitting devices suffered from very low degree of the radiation polarization. A hetero laser and light emitting device with a semiconductor layer sandwiched between ?-doped layers and ferromagnets allows for highly polarized light to be emitted.

Abstract: In a semiconductor laser 1, a current blocking layer 19 covers a p-type 2nd cladding layer 17 and a p-type cap layer 18 that extend in a lengthwise direction of an optical resonator, at both a light-emission end and an end opposite the light-emission end, to thus form non-current injection regions in an optical waveguide. By making current blocking layer 19 at the light-emission end large enough that carriers flowing from a current injection region do not reach the light-emission end surface, the light intensity distribution in the near field at the light-emission end surface is strongly concentrated, allowing the horizontal divergence angle of an emerging laser beam to be enlarged. This structure makes it possible to enlarge the horizontal divergence angle independently after having optimized the thickness of cladding layers and the size of the current injection region.

Abstract: A reliable high frequency VCSEL includes a lower distributed Bragg reflector (DBR), an active region, and an upper DBR. A cylindrical volume is etched from the upper DBR to define a mesa with a lower surface of the cylindrical volume forming an angle greater than ninety degrees with the side wall of the mesa. An isolation trench is etched in the lower surface of the cylindrical volume concentric with the mesa and extending through the active region. A portion of the side wall of the mesa and the lower surface of the cylindrical volume are proton implanted. The upper DBR is planarized using low-k dielectric materials and n and p electrical contacts are coupled to opposite sides of the active region for supplying operating current thereto.