Abstract: A light source device that supplies a constant current to a diode load that includes a plurality of light-emitting elements connected in series. The light source device includes a power supply circuit connected to the diode load and a peak current limiting circuit connected in series to the diode load. The peak current limiting circuit includes a current detector that is connected in series to the diode load and a current-regulating circuit that controls a current to the diode load by a detection voltage of the current detector. Further, the current detector has a series circuit including a resistor and a coil.

Abstract: A semiconductor laser element includes a substrate, and a semiconductor layer portion disposed on the substrate and including a waveguide including an active layer. The waveguide includes a wide portion including a first diffraction grating, and a narrow portion that has a narrower waveguide width than the wide portion and through which light generated in the active layer propagates in a transverse multimode. The waveguide includes a first end surface including an end surface of the narrow portion, and a second end surface located on a side opposite to the first end surface. The wide portion is continuously connected to the narrow portion, and includes a first region having a waveguide width increasing from the first end surface side toward the second end surface side.

Abstract: A light source device including: a first light source configured to coaxially combine a plurality of first laser beams, each having a peak wavelength within a first wavelength range, to thereby generate and emit a first wavelength-combined beam; a second light source configured to coaxially combine a plurality of second laser beams, each having a peak wavelength within a second wavelength range that defines a range of peak wavelengths shorter than the peak wavelengths in the first wavelength range, to thereby generate and emit a second wavelength-combined beam; and a wavelength filter configured to coaxially combine the first wavelength-combined beam and the second wavelength-combined beam to thereby generate and emit a third wavelength-combined beam.

Abstract: A wavelength beam combining device includes: a polarization beam splitter configured to separate the plurality of laser beams into a plurality of first polarized light beams linearly polarized in a first polarization direction and a plurality of second polarized light beams linearly polarized in a second polarization direction that is orthogonal to the first polarization direction; a first polarization conversion element configured to convert the second polarized light beams into a plurality of third polarized light beams linearly polarized in the first polarization direction; a diffraction grating configured to diffract the plurality of first polarized light beams and generate a coaxially combined first wavelength-combined beam, and to diffract the plurality of third polarized light beams and generate a coaxially combined second wavelength-combined beam; and a polarization beam combiner configured to generate and emit a third wavelength-combined beam into which the first wavelength-combined beam and the seco

Abstract: A light source device includes: a plurality of laser sources; a plurality of collimating parts, each configured to collimate the light beam emitted from a corresponding one of the laser sources; a combining grating configured to diffract, at an identical diffraction angle, light beams that have passed through the collimating parts and are incident on the combining grating at different incident angles to combine the diffracted light beams; and a plurality of volume holographic gratings, wherein each of the volume holographic gratings is disposed in an optical path between a corresponding one of the laser sources and the combining grating, wherein each of the volume holographic gratings determines a wavelength of the light beam incident on the combining grating, and wherein each of the volume holographic gratings is configured to diffract a portion of the light beam emitted from a corresponding laser source back to the laser source.

Abstract: A light source unit includes: a sealed semiconductor laser package including a laser diode that includes an emitter region from which laser light is emitted, the emitter region located at a surface of the laser diode, and a window member configured to transmit the laser light; a first lens structure configured to receive the laser light transmitted through the window member and create an image of the emitter region on an image plane; and a second lens structure configured to convert the laser light having passed through the image plane into a collimated or converged beam, and to emit the collimated or converged beam.

Abstract: A package for at least one laser diode includes: leads configured to be electrically connected to the at least one laser diode; a base including a mounting surface on which the at least one laser diode is to be mounted and a lateral wall located around the mounting surface so as to surround the at least one laser diode, the lateral wall defining first through-holes and including a light-transmissive part configured to transmit a laser beam emitted from the at least one laser diode; and a lead holding member bonded to the lateral wall of the base and defining second through-holes. The leads are disposed through the first through-holes and the second through-holes. At least a central portion of each of the leads is made of copper.

Abstract: A light source device includes an optical fiber; a beam light source configured to coaxially combine laser beams of different peak wavelengths to generate and emit a wavelength-combined beam; and an optical coupling device configured to allow the wavelength-combined beam emitted from the beam light source to be incident on the optical fiber. The optical coupling device includes a first cylindrical lens configured to focus the wavelength-combined beam in a first plane and having a first focal length, a second cylindrical lens configured to focus the wavelength-combined beam in a second plane and having a second focal length, and a third cylindrical lens having a third focal length greater than the first focal length and configured to focus the wavelength-combined beam in the first plane to be incident on the first cylindrical lens.

Abstract: A laser light source includes: a laser diode chip including an emission layer, a substrate supporting the emission layer, and an emission end surface; a submount that includes a principal surface on which the laser diode chip is fixed and a pair of lens supports located at opposite sides with respect to the emission end surface of the laser diode chip; a lens bonded to the end surfaces of the pair of lens supports; and a semiconductor laser package housing the aforementioned elements. The laser diode chip is fixed to the submount with the emission layer being closer to the submount than is the substrate. The emission end surface of the laser diode chip is located outward with respect to an edge of the principal surface. The end surfaces of the pair of lens supports are located outward with respect to the first end surface of the laser diode chip.

Abstract: A light source device that supplies a constant current to a diode load that includes a plurality of light-emitting elements connected in series. The light source device includes a power supply circuit connected to the diode load and a peak current limiting circuit connected in series to the diode load. The peak current limiting circuit includes a current detector that is connected in series to the diode load and a current-regulating circuit that controls a current to the diode load by a detection voltage of the current detector. Further, the current detector has a series circuit including a resistor and a coil.

Abstract: A semiconductor laser device includes: a support base having a plurality of mounting surfaces arranged in a first direction, wherein heights of the mounting surfaces from a reference plane that is parallel to the first direction decrease stepwise or gradually along the first direction; a first semiconductor laser element secured to a first mounting surface; a second semiconductor laser element secured to a second mounting surface; a first slow-axis collimator lens secured to the first mounting surface, the first slow-axis collimator lens being located at a position at which the first laser light is incident; a second slow-axis collimator lens directly or indirectly secured to the second mounting surface, the second slow-axis collimator lens being located at a position at which the second laser light is incident; and a first sealing cover that defines an inner space in which the first and second semiconductor laser elements are held.

Abstract: A laser light source includes: a submount having an upper surface; a semiconductor laser element located on the upper surface of the submount and having an end surface from which a laser beam is emitted; a lens facing the end surface of the semiconductor laser element; and a support member located on the upper surface of the submount and supporting the lens. The lens includes a collimating portion configured to collimate the laser beam emitted from the semiconductor laser element. The support member includes: a first portion and a second portion arranged at a lateral side of the submount; and a third portion that connects the first portion and the second portion and overlaps a portion of the semiconductor laser element in a plan view. The lens is supported by the first portion and the second portion via a bonding member.

Abstract: A light source device includes a plurality of external-cavity laser modules configured to emit a plurality of laser beams of different peak wavelengths, the plurality of external-cavity laser modules including at least one first laser module and at least one second laser module; and a beam combiner configured to coaxially combine the plurality of laser beams to generate a wavelength-combined beam. Each of the plurality of external-cavity laser modules includes: a collimation laser light source having a Littrow configuration, and a diffraction grating configured to selectively reflect and transmit light of a predetermined wavelength. The plurality of external-cavity laser modules are arranged so that the plurality of laser beams are incident on a same region of the beam combiner at different angles. A first distance between the first laser module and the beam combiner is different from a second distance between the second laser module and the beam combiner.

Abstract: An external cavity laser module is configured to emit a laser beam and includes: a collimation laser light source having a Littrow configuration; a diffraction grating configured to selectively reflect and transmit light of a specific wavelength; a support member supporting the collimation laser light source and the diffraction grating; and a base rotatably supporting the support member to correct an axial direction of the laser beam emitted from the external cavity laser module.

Abstract: A document reading apparatus includes a document supporting portion, a conveyance portion, a driving motor, an image reading unit, and a control portion. The control portion is configured to execute a high speed mode in which the conveyance speed is set to a first conveyance speed and a low speed mode in which the conveyance speed is set to a second conveyance speed slower than the first conveyance speed. When the control portion executes the low speed mode, if the document has a first thickness, the control portion is configured to execute a first low speed mode where a first drive speed is set to the driving motor. If the document has a second thickness thicker than the first thickness, the control portion is configured to execute a second low speed mode where a second drive speed faster than the first drive speed is set to the driving motor.

Abstract: A method of manufacturing a laser light source includes: providing a submount, the submount having a principal surface on which a laser diode chip is to be fixed, and comprising a pair of lens supports each including an end surface, the end surfaces located at opposite sides with respect to an emission end surface of the laser diode chip; providing a lens having a bonding surface; performing adjustment such that end surfaces of the pair of lens supports of the submount are parallel to a reference plane; performing adjustment such that the bonding surface of the lens is parallel to the reference plane; and while maintaining the end surfaces of the pair of lens supports and the bonding surface of the lens so as to be parallel to the reference plane, bonding the end surfaces with the bonding surface of the lens using an inorganic bonding member.

Abstract: A light source device including: a first light source configured to coaxially combine a plurality of first laser beams, each having a peak wavelength within a first wavelength range, to thereby generate and emit a first wavelength-combined beam; a second light source configured to coaxially combine a plurality of second laser beams, each having a peak wavelength within a second wavelength range that defines a range of peak wavelengths shorter than the peak wavelengths in the first wavelength range, to thereby generate and emit a second wavelength-combined beam; and a wavelength filter configured to coaxially combine the first wavelength-combined beam and the second wavelength-combined beam to thereby generate and emit a third wavelength-combined beam.

Abstract: A light source device includes: a plurality of laser sources; a plurality of collimating parts, each configured to collimate the light beam emitted from a corresponding one of the laser sources; a combining grating configured to diffract, at an identical diffraction angle, light beams that have passed through the collimating parts and are incident on the combining grating at different incident angles to combine the diffracted light beams; and a plurality of volume holographic gratings, wherein each of the volume holographic gratings is disposed in an optical path between a corresponding one of the laser sources and the combining grating, wherein each of the volume holographic gratings determines a wavelength of the light beam incident on the combining grating, and wherein each of the volume holographic gratings is configured to diffract a portion of the light beam emitted from a corresponding laser source back to the laser source.

Abstract: A package for at least one laser diode includes: leads configured to be electrically connected to the at least one laser diode; a base including a mounting surface on which the at least one laser diode is to be mounted and a lateral wall located around the mounting surface so as to surround the at least one laser diode, the lateral wall defining first through-holes and including a light-transmissive part configured to transmit a laser beam emitted from the at least one laser diode; and a lead holding member bonded to the lateral wall of the base and defining second through-holes. The leads are disposed through the first through-holes and the second through-holes. At least a central portion of each of the leads is made of copper.

Abstract: A light source device includes: a plurality of laser sources; a plurality of collimating parts, each configured to collimate the light beam emitted from a corresponding one of the laser sources; a combining grating configured to diffract, at an identical diffraction angle, light beams that have passed through the collimating parts and are incident on the combining grating at different incident angles, to combine the diffracted light beams; and a plurality of plane transmission gratings, wherein each of the plane transmission gratings is disposed in an optical path between a corresponding one of the collimating parts and the combining grating, and wherein each of the plane transmission gratings is adjustable so as to allow selection of a wavelength of the light beam incident on the combining grating.