Abstract: Provided are a dual mode semiconductor laser and a terahertz wave apparatus using the same. The dual mode semiconductor laser includes a distributed feedback laser structure section including a first diffraction grating on a substrate and a distributed Bragg reflector laser structure section including a second diffraction grating on the substrate. A first wavelength oscillated by the distributed feedback laser structure section and a second wavelength oscillated by the distributed Bragg reflector laser structure section are different from each other, and the distributed feedback laser structure section and the distributed Bragg reflector laser structure section share the same gain medium with each other.

Abstract: A high power pulsed laser system is configured with at least two gain blocks and with at least one saturable absorber (SA) coupled to the output and input of the respective gain blocks. The SA is configured so that Qsat_sa<Qsat_gb, wherein Qsat_sa is a saturation energy of the SA, and Qsat_gb is a saturation energy of the gain blocks. The SA is further configured with a recovery time ?<1/f providing for the substantially closed state of the SA, wherein the f is a pulse repetition rate, and with the recovery time ? smaller than a round trip time Tround_trip=2*(L1+L2)*n/c, where L1, L2—lengths of the respective gains gain blocks, n—a refractive index of active media, c—a speed of light in vacuum.

Abstract: A semiconductor vertical resonant cavity light source includes an upper mirror and a lower minor that define a vertical resonant cavity. A first active region is within the vertical resonant cavity for light generation between the upper minor and lower mirror. The vertical resonant cavity includes an inner mode confinement region and an outer current blocking region. A depleted heterojunction current blocking region (DHCBR) is within the outer current blocking region of at least one of the upper minor, lower minor, and first active region. A conducting channel within the inner mode confinement region is framed by the DHCBR. The DHCBR forces current flow into the conducting channel during operation of the light source.

Abstract: A driver device for a laser includes a control device configured to generate a control current, an NPN differential amplifier connected to the control device and configured to superimpose a modulation current onto the control current to generate a combined current, and a laser activation switch coupled to the output of the NPN differential amplifier, the laser activation switch operating the laser utilizing the combined current. Also described herein is a communication system including a driver device.

Abstract: Laser modules using two-dimensional laser diode arrays are combined to provide an intense laser beam. The laser diodes in a two-dimensional array are formed into rows and columns, and an optical assembly images light generated by laser diodes in a column into an optical fiber. The laser light outputs of the laser modules are combined by a spectral combiner into an optical fiber to form an intense laser beam.

Abstract: An object of the present invention is to provide a method and a device for constantly setting the energy distribution of a laser beam on an irradiating face, and uniformly irradiating the laser beam to the entire irradiating face. Further, another object of the present invention is to provide a manufacturing method of a semiconductor device including this laser irradiating method in a process. Therefore, the present invention is characterized in that the shapes of plural laser beams on the irradiating face are formed by an optical system in an elliptical shape or a rectangular shape, and the plural laser beams are irradiated while the irradiating face is moved in a first direction, and the plural laser beams are irradiated while the irradiating face is moved in a second direction and is moved in a direction reverse to the first direction.

Abstract: Embodiments of a method comprising guiding an optical mode with an optical waveguide disposed in silicon, overlapping both the optical waveguide and an active semiconductor material evanescently coupled to the optical waveguide with the optical mode guided through the optical waveguide, electrically pumping the active semiconductor material to inject current directed through the active semiconductor material and through the optical mode, and generating light in the active semiconductor material in response to the injected current. Other embodiments are disclosed and claimed.

Abstract: A light source, e.g., for optical excitation of a laser device, includes a diode laser having a large number of emitters and a light-guiding device, the light-guiding device including a large number of optical fibers. Each fiber has a first end and a lateral surface, the first ends being arranged relative to the emitters in such a manner that light generated by the emitters is coupled into the first ends of the optical fibers, the optical fibers being arranged in abutting relationship along their lateral surfaces at least in the region of their first ends. The optical fibers are connected in the region of their first ends to a fiber support.

Abstract: A light-emitting element includes a mesa structure in which a first compound semiconductor layer of a first conductivity type, an active layer, and a second compound semiconductor layer of a second conductivity type are disposed in that order, wherein at least one of the first compound semiconductor layer and the second compound semiconductor layer has a current constriction region surrounded by an insulation region extending inward from a sidewall portion of the mesa structure; a wall structure disposed so as to surround the mesa structure; at least one bridge structure connecting the mesa structure and the wall structure, the wall structure and the bridge structure each having the same layer structure as the portion of the mesa structure in which the insulation region is provided; a first electrode; and a second electrode disposed on a top face of the wall structure.

Abstract: A nitride-based semiconductor light-emitting device capable of suppressing complication of a manufacturing process and reduction of luminous efficiency is obtained. This nitride-based semiconductor light-emitting device (50) includes a nitride-based semiconductor device layer (23) formed on a main surface of a (1-100) plane of a substrate (21), having a light-emitting layer (26) having a main surface of a (1-100) plane, a facet (50a) formed on an end of a region including the light-emitting layer (26) of the nitride-based semiconductor device layer (23), formed by a (000-1) plane extending in a direction substantially perpendicular to the main surface ((1-100) plane) of the light-emitting layer (26), and a reflection surface (50c) formed on a region opposed to the facet (50a) of the (000-1) plane, formed by a growth surface of the nitride-based semiconductor device layer (23), extending in a direction inclined at an angle ?1 (about) 62° with respect to the facet (50a).

Abstract: A laser device is disclosed that provides at least an ultraviolet laser beam and preferably both an ultraviolet laser beam and a visible laser beam. The laser device includes a semiconductor laser device (e.g. a laser diode) to generate visible laser light which is coupled into a frequency doubling crystal taking the form of a single crystal thin film frequency-doubling waveguide structure. The single crystal thin film frequency-doubling waveguide converts a portion of the visible light emitted by the laser diode into ultraviolet light. Both visible and ultraviolet laser light is emitted from the waveguide. As an example, the single crystal thin film frequency-doubling frequency doubling waveguide includes a frequency doubling crystal region composed of ?-BaB2O4 (?-BBO), a cladding region composed of materials that are transparent or nearly transparent at the wavelength of the ultraviolet laser light beam and a supporting substrate composed of any material.

Abstract: There is provided a wavelength variable light source system capable of changing wavelength and intensity of output signal light and of improving preset accuracy and stability of the wavelength and strength of the output signal light. The system determines the both or either one of a target value for controlling wavelength and a target value for controlling intensity of output signal light of a wavelength variable light source by correlating a combination of the target wavelength and the target light output intensity specified from a higher-level device and controls operation states of the wavelength variable light source so that output values of monitoring circuits for monitoring the operation state of the wavelength variable light source converge to the target values.

Abstract: An optical assembly (OSA) that installs a semiconductor optical device mounted on a thermo-electric controller (TEC) is disclosed. The TEC in the upper plate thereof is mechanically connected to the housing, or to the block stiffly fixed to the housing by a bridge made of stiff material. The bridge preferably extends along the optical axis to show enhanced durability against the impact caused by an external ferrule abutting against the receptacle of the OSA.

Abstract: A nitride semiconductor laser device is provided herein that is reduced in capacitance to have a better response. The nitride semiconductor laser device includes: an active layer; an upper cladding layer which is stacked above the active layer; a low dielectric constant insulating film which is stacked above the upper cladding layer; and a pad electrode which is stacked above the low dielectric constant insulating film.

Abstract: A laser crystallization apparatus and method are disclosed for selectively melting a film such as amorphous silicon that is deposited on a substrate. The apparatus may comprise an optical system for producing stretched laser pulses for use in melting the film. In still another aspect of an embodiment of the present invention, a system and method are provided for stretching a laser pulse. In another aspect, a system is provided for maintaining a divergence of a pulsed laser beam (stretched or non-stretched) at a location along a beam path within a predetermined range. In another aspect, a system may be provided for maintaining the energy density at a film within a predetermined range during an interaction of the film with a shaped line beam.

Abstract: A semiconductor laser includes a gain region; a distributed Bragg reflector (DBR) region including a diffraction grating; an end facet facing the DBR region with the gain region arranged therebetween; a first ring resonator including a first ring-like waveguide and a first optical coupler; a second ring resonator including a second ring-like waveguide and a second optical coupler; and an optical waveguide that is optically coupled to the end facet and extending in a predetermined optical-axis direction. The first and second ring resonators are optically coupled to the optical waveguide through the first and second optical couplers, respectively. Also, the DBR region, the gain region, and the end facet constitute a laser cavity. Further, the first ring resonator has a free spectral range different from a free spectral range of the second ring resonator.

Abstract: A fiber optic network having a multi-level architecture is disclosed. A first level of the fiber optic network comprises a first branch. The first branch comprises a plurality of first branch optical fibers optically coupled to a distribution cable and a first branch fiber optic network device. The first branch fiber optic network device is configured to optically couple a first predetermined one of the plurality of first branch optical fibers to a respective first predetermined sub-branch optical fiber, and a second predetermined one of the plurality of first branch optical fibers to a second predetermined sub-branch optical fiber. A second level of the fiber optic network comprises a sub-branch. The sub-branch comprises a first sub-branch fiber optic network device and a second sub-branch fiber optic network device.

Abstract: The invention is directed to a laser catheter (1) for bypass surgery, wherein the distal part (2) of the catheter (1) is provided with: a tubular arrangement (3) of optical fibers (4) having distal ends (5) defining a ring-shaped light emergence surface (6) for emitting a tubular bundle of light beams in the distal direction (D) of the catheter (1); and a stop surface (7) extending around the tubular arrangement (3) of optical fibers (4) and facing in the distal direction (D), the stop surface (7) being arranged at a distance (A) proximally from the light emergence surface (6). The light emergence surface (6) slants at a slanting angle (?) in the range of [20°, 60°] with respect to the longitudinal axis (8) of the catheter (1). The invention further relates to an assembly comprising such a catheter.

Abstract: Methods and systems for split voltage domain receiver circuits are disclosed and may include amplifying complementary received signals in a plurality of partial voltage domains. The signals may be combined into a single differential signal in a single voltage domain. Each of the partial voltage domains may be offset by a DC voltage from the other partial voltage domains. The sum of the partial domains may be equal to a supply voltage of the integrated circuit. The complementary signals may be received from a photodiode. The amplified received signals may be amplified via stacked common source amplifiers, common emitter amplifiers, or stacked inverters. The amplified received signals may be DC coupled prior to combining. The complementary received signals may be amplified and combined via cascode amplifiers. The voltage domains may be stacked, and may be controlled via feedback loops. The photodetector may be integrated in the integrated circuit.

Abstract: Architectures for coherently combining an array of fiber-based lasers are provided. By matching their lengths to within a few integer multiples of a wavelength, the spatial and temporal properties of a single large laser are replicated, while extending the average or peak pulsed power limit.