Abstract: Provided is a semiconductor laser device which can generate an ultra-short pulse light. A semiconductor laser device disclosed herein includes a semiconductor laser unit that performs a gain-switching operation using a relaxation oscillation mechanism to generate a first pulse and a following component of the first pulse, and a filter that processes an output from the semiconductor laser unit by removing a signal in a wavelength bandwidth generated due to at least the following portion in a wavelength bandwidth broadened by chirping. The filter is configured as a short pass filter which passes a short-wavelength component. Further, an apparatus using non-linear optical effect which uses the semiconductor laser device is also provided.

Abstract: A laser diode assembly includes: a mode-locked laser diode device; a diffraction grating that configures an external resonator, returns primary or more order diffracted light to the mode-locked laser diode device, and outputs 0-order diffracted light outside; and an imaging section provided between the mode-locked laser diode device and the diffraction grating and imaging an image of a light output end face of the mode-locked laser diode device on the diffraction grating.

Abstract: The microscope apparatus includes a light source which outputs linear polarization having a first wavelength, a polarization conversion element which includes a liquid crystal layer, and by causing linear polarization to pass the liquid crystal layer, converts linear polarization to radial polarization, an objective lens which focuses the radial polarization onto an object surface, a condenser lens which collimates the light reflected from the object surface, a light receiving element which receives light collimated by the condenser lens and outputs signal in accordance with the intensity of light, and a controller which applies electric voltage in accordance with the first wavelength to the liquid crystal layer of the polarization conversion element. The polarization conversion element is disposed in the pupil plane of the objective lens on the light source side.

Abstract: A laser diode assembly includes a mode-locked laser diode device, where a light output spectrum shows long-wavelength shift by self-phase modulation, an external resonator, and a wavelength selective element. A long wavelength component of a pulsed laser beam emitted through the external resonator from the mode-locked laser diode device is extracted by the wavelength selective element, and output to the outside.

Abstract: A laser diode assembly includes: a mode-locked laser diode device; a diffraction grating that configures an external resonator, returns primary or more order diffracted light to the mode-locked laser diode device, and outputs 0-order diffracted light outside; and an imaging section provided between the mode-locked laser diode device and the diffraction grating and imaging an image of a light output end face of the mode-locked laser diode device on the diffraction grating.

Abstract: Provided is a heating device which is capable of smoothening flow of a heat medium while reducing a processing time of a case. A heating device 1 is constituted of a case 2 including therein a flow path 3 through which a heat medium flows, and electric heating wire heaters 4 arranged in the flow path 3 of the case 2 to heat the heat medium. The case 2 is constituted of a first case section 6 and a second case section 7 each of which has at least one opened surface and which are connected to each other in a state where respective openings 6A and 7A are made to abut on each other. The respective case sections 6 and 7 are formed by casting of a metal.

Abstract: Provided is a heating device which makes it possible to effectively perform heat exchange between a heating element and a heat medium without increasing the number of components, and further to eliminate air retention and increase of a pressure loss. A heating device 1 is constituted of a case 2 including therein a flow path 3 through which a heat medium flows, and an electric heating wire heater 4 disposed in the flow path of the case to heat the heat medium. The case comprises a first case section 6 and a second case section 7 each of which has at least one opened surface and which are connected to each other in a state where respective openings are made to abut on each other, and a plate-like gasket 8 which is interposed between abutment portions of the first case section and the second case section, and seals a space between both the case sections, and the gasket controls the flow of the heat medium in the flow path.

Abstract: A laser diode device includes a laminated structure in which a first compound semiconductor layer, a third compound semiconductor layer that has a light emitting region and a saturable absorption region, and a second compound semiconductor layer are sequentially layered, a second electrode, and a first electrode. The laminated structure has ridge stripe structure. The second electrode is separated into a first section to obtain forward bias state by applying a direct current to the first electrode through the light emitting region and a second section to add electric field to the saturable absorption region by an isolation trench. When minimum width of the ridge stripe structure is WMIN, and width of the ridge stripe structure of the second section of the second electrode in an interface between the second section of the second electrode and the isolation trench is W2, 1<W2/WMIN is satisfied.

Abstract: An ultrashort pulse and ultrahigh power laser diode device capable of outputting pulse laser light having higher peak power with a simple composition and a simple structure is provided. The laser diode device includes: a laminated structure composed of a first compound semiconductor layer containing n-type impurity, an active layer having a quantum well structure, and a second compound semiconductor layer containing p-type impurity; a first electrode electrically connected to the first compound semiconductor layer; and a second electrode electrically connected to the second compound semiconductor layer, wherein the second compound semiconductor layer is provided with an electron barrier layer having a thickness of 1.5*10?8 m or more, and driving is made by a pulse current having a value 10 or more times as large as a threshold current value.

Abstract: A submount having a structure and a configuration resistant to an increase in manufacturing cost and a reduction in yields or reliability, and including an oblique waveguide is provided. A submount having a first surface and allowing a semiconductor light-emitting element including a waveguide to be fixed on the first surface, the waveguide having an axis line inclined at ?WG (degrees) with respect to a normal to a light-incident/emission end surface of the semiconductor light-emitting element, and made of a semiconductor material with a refractive index nLE, the submount includes: a fusion-bonding material layer on the first surface; and an alignment mark formed in the fusion-bonding material layer, the alignment mark allowed to be recognized at an angle ?SM=sin?1 [nLE·sin(?WG)/n0], where a refractive index of a light-transmitting medium in proximity to the outside of the light-incident/emission end surface of the semiconductor light-emitting element is n0.

Abstract: Provided is an alignment method of a semiconductor optical amplifier with which optimization of coupling efficiency between incident laser light and light waveguide of the semiconductor optical amplifier is enabled without depending on an external monitoring device. The alignment method of a semiconductor optical amplifier is a method that optically amplifies laser light from a laser light source and outputs the optically amplified laser light, which adjusts relative position of the semiconductor optical amplifier with respect to the laser light entering into the semiconductor optical amplifier by flowing a given value of current to the semiconductor optical amplifier while entering the laser light from the laser light source to the semiconductor optical amplifier so that a voltage applied to the semiconductor optical amplifier becomes the maximum.

Abstract: Provided is a semiconductor laser device which can generate an ultra-short pulse light. A semiconductor laser device disclosed herein includes a semiconductor laser unit that performs a gain-switching operation using a relaxation oscillation mechanism to generate a first pulse and a following component of the first pulse, and a filter that processes an output from the semiconductor laser unit by removing a signal in a wavelength bandwidth generated due to at least the following portion in a wavelength bandwidth broadened by chirping. The filter is configured as a short pass filter which passes a short-wavelength component. Further, an apparatus using non-linear optical effect which uses the semiconductor laser device is also provided.

Abstract: There is provided a driving method of a self-oscillating semiconductor laser device including a first compound semiconductor layer having a first conductive type and composed of a GaN base compound semiconductor, a third compound semiconductor layer and a second compound semiconductor layer configuring an emission region and a saturable absorption region, are successively laminated, a second electrode formed on the second compound semiconductor layer, and a first electrode electrically connected to the first compound semiconductor layer. The second electrode is separated into a first portion to create a forward bias state by passing current to the first electrode via the emission region and a second portion to apply an electric field to the saturable absorption region by a separation groove. The current greater than a current value where kink is occurred in optical output-current characteristics is to be passed to the first portion of the second electrode.

Abstract: A semiconductor optical amplifier includes: a laminated structure sequentially including a first compound semiconductor layer composed of GaN compound semiconductor and having a first conductivity type, a third compound semiconductor layer having a light amplification region composed of GaN compound semiconductor, and a second compound semiconductor layer composed of GaN compound semiconductor and having a second conductivity type; a second electrode formed on the second compound semiconductor layer; and a first electrode electrically connected to the first compound semiconductor layer. The laminated structure has a ridge stripe structure. When widths of the ridge stripe structure in a light output end face and the ridge stripe structure in a light incident end face are respectively Wout, and Win, Wout>Win is satisfied. A carrier non-injection region is provided in an internal region of the laminated structure from the light output end face along an axis line of the semiconductor optical amplifier.

Abstract: A laser diode assembly includes: a mode-locked laser diode device; a diffraction grating that configures an external resonator, returns primary or more order diffracted light to the mode-locked laser diode device, and outputs 0-order diffracted light outside; and an imaging section provided between the mode-locked laser diode device and the diffraction grating and imaging an image of a light output end face of the mode-locked laser diode device on the diffraction grating.

Abstract: A laser diode capable of performing self-pulsation operation, and capable of sufficiently reducing the coherence of laser light and stably obtaining low-noise laser light is provided. The laser diode includes: a laser chip including at least one laser stripe which extends in a resonator length direction between a first end surface and a second end surface opposed to each other, in which the laser stripe includes a gain region and a saturable absorption region in the resonator length direction, and the width of the laser stripe in the saturable absorption region is larger than the width of the laser stripe in the gain region.

Abstract: A laser diode capable of performing self-pulsation operation, and capable of sufficiently reducing the coherence of laser light and stably obtaining low-noise laser light is provided. A laser diode includes: a laser chip including at least one laser stripe which extends in a resonator length direction between a first end surface and a second end surface opposed to each other, in which the laser stripe includes a gain region and a saturable absorption region in the resonator length direction, and the width of the laser stripe in the saturable absorption region is larger than the width of the laser stripe in the gain region.

Abstract: An ultrashort pulse/ultra-high power laser diode with a simple structure and configuration is provided. In a method of driving a laser diode, the laser diode is driven by a pulse current which is 10 or more times higher than a threshold current value. The width of the pulse current is preferably 10 nanoseconds or less, and the value of the pulse current is specifically 0.4 amperes or over.

Abstract: A method for manufacturing a bi-section semiconductor laser device includes the steps of (A) forming a stacked structure obtained by stacking, on a substrate in sequence, a first compound semiconductor layer of a first conductivity type, a compound semiconductor layer that constitutes a light-emitting region and a saturable absorption region, and a second compound semiconductor layer of a second conductivity type; (B) forming a belt-shaped second electrode on the second compound semiconductor layer; (C) forming a ridge structure by etching at least part of the second compound semiconductor layer using the second electrode as an etching mask; and (D) forming a resist layer for forming a separating groove in the second electrode and then forming the separating groove in the second electrode by wet etching so that the separating groove separates the second electrode into a first portion and a second portion.

Abstract: A semiconductor optical amplifier includes: a laminated structure sequentially including a first compound semiconductor layer composed of GaN compound semiconductor and having a first conductivity type, a third compound semiconductor layer having a light amplification region composed of GaN compound semiconductor, and a second compound semiconductor layer composed of GaN compound semiconductor and having a second conductivity type; a second electrode formed on the second compound semiconductor layer; and a first electrode electrically connected to the first compound semiconductor layer. The laminated structure has a ridge stripe structure. When widths of the ridge stripe structure in a light output end face and the ridge stripe structure in a light incident end face are respectively Wout, and Win, Wout>Win is satisfied. A carrier non-injection region is provided in an internal region of the laminated structure from the light output end face along an axis line of the semiconductor optical amplifier.