Abstract: A mode hop-free tunable laser including a gain medium, a microfabricated blazed grating, defining an external cavity of a given length, the blazed grating lying in a general plane and including a plurality of elongate beams carrying mutually parallel respective reflection surfaces spaced apart from one another with a predefined pitch, and actuating elements designed so as to allow displacements of the assembly with respect to a grating support within a plane substantially parallel to the grating general plane, and including actuation elements designed so as to apply a stretching and a displacement of the assembly in a direction transverse to said reflection surfaces, the blazed grating being arranged relative to an incident light beam provided by the gain medium so that the incident light beam impinges on the reflection surfaces with a substantially normal incident angle.

Abstract: A laser having a laser cavity is disclosed that does not require conventional dielectric mirrors or as-grown reflectors. Instead, a diffraction grating and total internal reflection system is used to define a laser cavity. Within the laser cavity, the laser emission travels in a zigzag pattern. The diffraction grating provides a highly reflective “mirror” diffracting beams at a forward angle and back angle that “tunes” the process of total internal reflection. The diffraction grating also directs a small percentage of the incident radiation approximately normal to the upper face of the semiconductor (more generally, at an angle less than the critical angle), to provide an output laser beam. The laser can be used in an electron tube and laser display system.

Abstract: A semiconductor laser element realizes a high COD light output in broader range of reflection factor at a facet with high reliability. A semiconductor laser element has a multi-layered reflection film formed on at least one end facet of a resonator. An optical path length of each layer of said multi-layered reflection film is determined by (2m?1)·?/4, where ? is oscillation wavelength, and m is positive integer). A high-refractive-index layer and a low-refractive-index layer are alternately stacked starting from a first layer adjacent to said semiconductor.

Abstract: An active element for a laser source, the active element comprising an elongated bar with a reflective lateral surface, doped to be able to absorb at least a pumping beam being propagated at least approximately longitudinally in the bar in order to amplify at least a laser radiation also being propagated longitudinally; and a jacket in contact with the lateral surface of the bar and presenting a refractive index smaller than that of the bar, in the reflective lateral surface of the bar, there is at least one dull-ground diffusing zone able to interrupt the paths of spurious laser modes being propagated in the bar by total internal reflections on the lateral surface.

Abstract: The present invention provides a semiconductor optical element applicable to an EC-LD or an SLD, and an external cavity laser having the semiconductor optical element. The semiconductor optical element has a pair of cleavage surfaces, and comprises a semiconductor substrate 11 having a base surface and a planer structure provided on the base surface and provided with a waveguide 1G having an active layer. The waveguide 1G has an end surface with low reflectivity and another end surface with certain reflectivity.

Abstract: The optical fiber 1 for an optical fiber laser is provided with a rare earth element doped core 2 doped with a rare earth element, and a cladding 3 formed at an outer periphery of the rare earth element doped core 2. In the optical fiber 1 for an optical fiber laser, the rare earth element doped core 2 is divided into a plurality of core regions 2a, 2b, . . . , 2n?1, 2n along a longitudinal direction of the optical fiber 1 and dopant concentrations of the rare earth element in respective core regions 2a, 2b, . . . , 2n?1, 2n are different from each other, in order to flatten a temperature distribution of the optical fiber 1 along the longitudinal direction.

Abstract: A method of controlling a semiconductor laser that has a plurality of wavelength selection portions having a different wavelength property from each other and is mounted on a temperature control device, including: a first step of correcting a temperature of the temperature control device according to a detected output wavelength of the semiconductor laser; and a second step of controlling at least one of the wavelength selection portions so that changing amount differentials between each wavelength property of the plurality of the wavelength selection portions is reduced, the changing amount differential being caused by correcting the temperature of the temperature control device.

Abstract: A laser array circuit decreases the size of a circuit pattern. A laser-diode (LD) driving switching element with a low on resistance is used in common with and switches conduction and non-conduction of a large current to each of a plurality of charge capacitors and charge switching elements that accumulate charge in the charge capacitors in respective drive circuits. An LD array and the LD driving switching element are closely located on a light-emitting board. By laying out the LD array and charge capacitors considering only the positional relationship therebetween, the size of a circuit pattern including LDs and the charge capacitors can be decreased.

Abstract: Apparatus and method for driving laser diodes with electrical power in pulsed operation. Pulsed power, for example using pulse-width modulation, is applied through an inductor in one or more parallel regulator circuits having little or no output capacitance to provide a high-efficiency laser-diode-driver power supply. Some embodiments that use two or more parallel regulator circuits in the laser-diode driver, drive each from a different phase of a clock signal. Some embodiments provide a first DC-to-DC converter has a relatively high-voltage input (e.g., about 275 volts, 0.75 amps) and an intermediate output of, e.g., 11 to 15 volts, 15 to 11 amps used to charge a storage capacitor, and a second DC-to-DC converter diode driver having one or more parallel circuits (each having, e.g., a PWM switching-mode controller and its respective switch, inductor, and diode) to turn on, regulate, and turn off a constant laser-diode current through one or more laser diodes.

Abstract: A fiber laser with reduced stimulated Brillouin scattering includes a spool having a height and characterized by an induced temperature gradient with the height. The fiber laser also includes a fiber wrapped on the spool and characterized by a signal power increasing along the length of the fiber. The induced temperature gradient is a function of the signal power along the fiber.

Abstract: Disclosed is a laser driving technique capable of reducing power consumption in a laser driving circuit to achieve reduced heat generation in an optical pickup of a recording/reading equipment for an optical disc. A base-voltage control circuit is connected to a base of a grounded-base cascode transistor connected between a driver circuit and a laser diode (LD), and a LD-anode-voltage control circuit is connected to an anode of the laser diode. The base-voltage control circuit and the LD-anode-voltage control circuit are connected to a controller, and operable to variously change an anode voltage of the laser diode and a base voltage of the cascode transistor depending on a driving current for the laser diode.

Abstract: A laser diode and method for fabricating same, wherein the laser diode generally comprises an InGaN compliance layer on a GaN n-type contact layer and an AlGaN/GaN n-type strained super lattice (SLS) on the compliance layer. An n-type GaN separate confinement heterostructure (SCH) is on said n-type SLS and an InGaN multiple quantum well (MQW) active region is on the n-type SCH. A GaN p-type SCH on the MQW active region, an AlGaN/GaN p-type SLS is on the p-type SCH, and a p-type GaN contact layer is on the p-type SLS. The compliance layer has an In percentage that reduces strain between the n-type contact layer and the n-type SLS compared to a laser diode without the compliance layer. Accordingly, the n-type SLS can be grown with an increased Al percentage to increase the index of refraction. This along with other features allows for reduced threshold current and voltage operation.

Abstract: A semiconductor laser, having an active layer with a double-quantum-well structure, includes two InGaN well layers, each of which has a thickness of 5 nm. The threshold current deteriorates to a relatively small degree while differential efficiency is improved considerably in a region having a light confinement coefficient ? of 3.0% or less. The light confinement coefficient indicates the proportion of light in the well layers with respect to light in the light emitting device, during light emission. When the light confinement coefficient ? is less than 1.5%, the threshold current increases considerably and the improvement in differential efficiency becomes small. It is therefore preferable that the lower limit of the light confinement coefficient ? be about 1.5%. A differential efficiency of 1.6 W/A or more is obtained when light the confinement coefficient ? is 3.0% or less, and a differential efficiency of 1.7 W/A or more is obtained when the light confinement coefficient ? is 2.6% or less.

Abstract: A compact optically-pumped solid-state laser designed for efficient nonlinear intracavity frequency conversion into desired wavelengths using periodically poled nonlinear crystals. These crystals contain dopants such as MgO or ZnO and/or have a specified degree of stoichiometry that ensures high reliability. The laser includes a solid-state gain media chip, such as Nd:YVO4, which also provides polarization control of the laser; and a periodically poled nonlinear crystal chip such as PPMgOLN or PPZnOLT for efficient frequency doubling of the fundamental infrared laser beam into the visible wavelength range. The described designs are especially advantageous for obtaining low-cost green and blue laser sources.

Abstract: A laser assembly is suitable for coupling laser light into at least one optical fiber. The laser assembly contains a plurality of laser light sources disposed spaced from a light entrance surface of the at least one optical fiber. The laser light sources are divided into at least one group of first laser light sources and at least one group of second laser light sources. An aperture is provided and is suitable for spatially confining the laser light emitted during operation of the laser light sources before being coupled into the at least one optical fiber. A coupling device is provided and is suitable for coupling the laser light during operation of the first and second laser light sources before it enters into the at least one optical fiber.

Abstract: A laser diode package according to the present invention is composed of CTE mismatched components soldered together. The laser diode package includes a laser diode bar, at least one heat sink, and at least one exothermic layer. Solder layers are adjacent the heat sink(s) and laser diode bar, respectively. The exothermic layer(s) are positioned between the solder layers. The exothermic layer(s) are exposed to an energy source which causes an exothermic reaction to propagate through the exothermic layer thereby melting the solder layers and solder layers. The exothermic layer(s) may be designed to provide sufficient heat to melt the solder layers and solder layers but provide only minimal heat to the laser diode bar and heat sink(s). Several packages can be stacked together to form a laser diode array.

Abstract: A surface-emission laser device comprises an active layer, cavity spacer layers provided at both sides of the active layer, reflection layers provided at respective sides of the cavity spacer layers, the reflection layers reflecting an oscillation light oscillated in the active layer and a selective oxidation layer. The selective oxidation layer is provided between a location in the reflection layer corresponding to a fourth period node of the standing wave distribution of the electric field of the oscillating light and a location in the reflection layer adjacent to the foregoing fourth period node in the direction away from the active layer and corresponding to an anti-node of the standing wave distribution of the electric field of the oscillation light.

Abstract: In a solid-state laser amplifier including at least two laser-active media in a common laser radiation field, the laser-active media do not form a hard aperture for the laser radiation field. Each of the laser-active media define a plane that is penetrated by the laser radiation field. The laser amplifier includes at least one focusing optical element disposed in the laser radiation field between two adjacent laser-active media. A focal length and a distance of the focusing optical element from the planes of the two adjacent laser-active media are selected such that the planes of the laser-active media are approximately mapped onto each other by a near-field far-field transformation.

Abstract: A Littrow-type external-cavity diode laser optical axis displacement correction method and device to easily, inexpensively, and accurately correct displacement of optical axis in Littrow-type ECDLs is provided. In the Littrow-type ECDL optical axis displacement correction device and method, a means for introducing a laser beam, a jig 36 for integrally fixing a diffraction grating 33 and a prism 35 into which the laser beam is introduced in a predetermined arrangement, and a rotary shaft 34 capable of integrally rotating the diffraction grating 33 and the prism 35 are included. By the rotation of the diffraction grating 33 and the prism 35 around the rotary shaft 34, the wavelength of the incident light can be changed, and the optical axis of the output light 39 is not changed by the change of the wavelength.

Abstract: A laser diode driving apparatus comprising an oscillator (11) for generating a high-frequency signal; an amplifier (12) for amplifying the high-frequency signal and outputting the amplified high-frequency signal; current mirror circuits (7, 8 and 9) for receiving the output current of the amplifier (12) and driving multiple laser diodes (1, 2 and 3), respectively; a DC current supply source (10) for supplying a DC current to the current mirror circuits, wherein the laser diode is driven using a current obtained by superimposing the high-frequency signal on the DC current, the laser diode driving apparatus further comprising a high-frequency signal superimposed amplitude setting circuit (14) for changing the amplitude of the amplifier so as to be suited for the selection of the current mirror circuit.