Abstract: A multi-beam laser light-intensity control circuit includes laser diodes; a light-receiving element for receiving a laser beam emitted from each laser diode and outputting a current corresponding to the light intensity of the received laser beam; and an automatic power control circuit for automatically controlling output power of each laser diode based on the current output from the light-receiving element.

Abstract: A semiconductor laser according to the present invention comprises a ?/2 dielectric film (?:in-medium wavelength of a dielectric film, for example, SiO2, Si3N4, Al2O3, and AlN) in contact with a facet of a resonator; and a first dielectric double layered film disposed on the dielectric film, which includes a first layer of a-Si and a second layer of a material having a refractive index lower than that of a-Si. The first layer has a thickness ¼ of an in-medium wavelength of a-Si, and the second layer has a thickness ¼ of an in-medium wavelength of the second layer. Therefore, it is possible to firmly stack the first dielectric double layered film and form a high reflectance film with high yield.

Abstract: An optical waveguide integrated semiconductor optical device includes a laser and an optical waveguide. The laser includes an active layer and a first cladding layer which are stacked on a second cladding layer. The optical waveguide includes an optical guiding layer and an undoped InP layer which are also stacked on the second cladding layer. A high resistance layer is located between the top surface of the optical guiding layer and a surface of the undoped InP layer and between a side of the first cladding layer and a side of the undoped InP layer.

Abstract: A system generates FIR laser radiation. An electron source generates an electron beam. A grating horn interacts with the electron beam to produce the FIR laser radiation. The grating horn may comprise a flat base and a pair of grating elements attached to the base, each of the grating elements being ruled with a grating period, the grating elements oriented in phase and in substantial symmetry about a normal to the flat base.

Abstract: A method of generating laser pulses having a predefined amplitude, phase and/or polarization at a distal end of an optical transmission system having at least one optical fiber, includes the steps of: generating laser pulses and inputting the laser pulses into a pulse shaper; calculating a control signal for controlling the pulse shaper, wherein at least one physical parameter of the optical fiber is taken into account; applying the control signal to the pulse shaper and modulating the amplitude, phase and/or polarization of the laser pulses whereby modulated laser pulses are formed; and inputting the modulated laser pulses into a proximal end of the optical transmission system.

Abstract: A compact semiconductor laser pumped solid-state laser device is provided that can suppress unnecessary parasitic oscillation in a microchip and efficiently extract energy.

Abstract: Designs and processes for thermally stabilizing a vertical cavity surface emitting laser (vcsel) in a chip-scale atomic clock are provided. In one embodiment, a Chip-Scale Atomic Clock includes: a vertical cavity surface emitting laser (vcsel); a heater block coupled to a base of the vcsel; a photo detector; a vapor cell, wherein the vapor cell includes a chamber that defines at least part of an optical path for laser light between the vcsel and the photo detector; and an iso-thermal cage surrounding the vcsel on all sides, the iso-thermal cage coupled to the heater block via a thermally conductive path.

Abstract: A disclosed surface emitting laser is capable of being manufactured easily, having a higher yield and a longer service lifetime. In the surface emitting laser, a selectively-oxidized layer is included as a part of a low refractive index layer of an upper semiconductor distribution Bragg reflector; the low refractive index layer including the selectively-oxidized layer includes two intermediate layers adjoining the selectively-oxidized layer and two low refractive index layers adjoining the intermediate layers. Al content rate in the intermediate layers is lower than that in the selectively-oxidized layer, and Al content rate in the low refractive index layers is lower than that in the selectively-oxidized layer. This configuration enables providing more control over the thickness and oxidation rate of the oxidized layer, thereby enabling reducing the variation of the thickness of the oxidized layer.

Abstract: The configurations of an electro-optic Bragg deflector and the methods of using it as a laser Q-switch in a Q-switched laser and in a Q-switched wavelength-conversion laser are provided. As a first embodiment, the electro-optic Bragg deflector comprises an electrode-coated electro-optic material with one of a 1D and a 2D spatially modulated electro-optic coefficient. When a voltage is supplied to the electrodes, the electro-optic material behaves like a Bragg grating due to the electro-optically induced spatial modulation of the refractive index. The second embodiment relates to an actively Q-switched laser, wherein the electro-optic Bragg deflector functions as a laser Q-switch. The third embodiment of the present invention combines the Q-switched laser and a laser-wavelength converter to form a Q-switched wavelength-conversion laser, wherein the EO Bragg deflector can be monolithically integrated with a quasi-phase-matching wavelength converter in a fabrication process.

Abstract: A wavelength tuneable external-cavity laser module comprises a gain medium in thermal contact with a thermally stabilized substrate; an end mirror, and a phase element for controlling the phase of the optical beam and being positioned within the external cavity between the gain medium and the end mirror, wherein said phase element comprises a material having a refractive index that varies in response to changes in temperature and has a transmissivity substantially independent of wavelength across said predetermined wavelength range. The thermally-controllable phase element is configured so as to induce a phase variation that compensates the drop in the output power due to ageing or to external temperature variation. A heating element is placed in thermal contact to the phase element. By thermally controlling an intra-cavity phase element it is possible to vary continuously the output power as a function of the injection current.

Abstract: A method of fabricating group-III nitride semiconductor laser device includes: preparing a substrate comprising a hexagonal group-III nitride semiconductor and having a semipolar principal surface; forming a substrate product having a laser structure, an anode electrode, and a cathode electrode, where the laser structure includes a semiconductor region and the substrate, where the semiconductor region is formed on the semipolar principal surface; scribing a first surface of the substrate product in a direction of an a-axis of the hexagonal group-III nitride semiconductor to form first and second scribed grooves; and carrying out breakup of the substrate product by press against a second surface of the substrate product, to form another substrate product and a laser bar.

Abstract: A semiconductor laser element is provided which includes a first semiconductor layer, an active layer having a current injection region, a second semiconductor layer, a third semiconductor layer, and an electrode for injecting a current into the active layer. In the semiconductor laser element, the first semiconductor layer, the active layer, the second semiconductor layer, and the third semiconductor layer are laminated in that order on a substrate, the first semiconductor layer has a current constriction layer which constricts the current injection region of the active layer, the third semiconductor layer is formed on an upper surface of the second semiconductor layer in a region corresponding to the current injection region of the active layer, and the electrode is formed on the upper surface of the second semiconductor layer in a region other than that of the third semiconductor layer.

Abstract: Embodiments of the invention include a laser structure having a delta doped active region for improved carrier confinement. The laser structure includes an n-type cladding layer, an n-type waveguide layer formed adjacent the n-type cladding layer, an active region formed adjacent the n-type waveguide layer, a p-type waveguide layer formed adjacent the active region, and a p-type cladding layer formed adjacent the p-type waveguide layer. The laser structure is configured so that a p-type dopant concentration increases across the active region from the n-type side of the active region to the p-type side of the active region and/or an n-type dopant concentration decreases across the active region from the n-type side of the active region to the p-type side of the active region. The delta doped active region provides improved carrier confinement, while eliminating the need for blocking layers, thereby reducing stress on the active region caused thereby.

Abstract: The present invention provides a semiconductor laser including a first conductive type of a lower clad layer 12, an active layer 14 provided on the lower clad layer 12, the active layer 14 including a plurality of quantum dots, and a second conductive type of an upper clad layer 18, the upper clad layer 18 being provided on the active layer 14 so as to have an isolated ridge portion 30 such that W1?Wtop+0.4 ?m where Wtop is the width of a top of the ridge portion 30 and W1 is the width of the ridge portion 30 at a height of 50 nm from a bottom of the ridge portion 30. The present invention also provides a method for manufacturing such a semiconductor laser.

Abstract: A semiconductor laser includes a semiconductor laser region and a wavelength-monitoring region. The semiconductor laser region includes a first optical waveguide that includes a gain waveguide, the first optical waveguide having one end and another end opposite the one end. The wavelength-monitoring region includes a second optical waveguide that is optically coupled to the first optical waveguide with the one end therebetween, and a photodiode structure that is optically coupled to the second optical waveguide. In the wavelength-monitoring region, the second optical waveguide is branched into three or more optical waveguides, and at least two optical waveguides among the three or more optical waveguides form first ring resonators having optical path lengths different from each other.

Abstract: A photonic crystal laser comprises an n-type substrate, an n-type clad layer, an active layer, a p-type clad layer, a photonic crystal layer, a p-type electrode, an n-type electrode and a package member. The n-type clad layer is formed on a first surface of the n-type substrate. The active layer is formed on the n-type clad layer. The p-type clad layer is formed on the active layer. The photonic crystal layer is formed between the n-type clad layer and the active layer or between the active layer and the p-type clad layer, and includes a photonic crystal portion. The p-type electrode is formed on the photonic crystal portion. The n-type electrode is formed on a second surface, and includes a light-transmitting portion arranged on a position opposed to the photonic crystal portion and an outer peripheral portion having lower light transmittance than the light-transmitting portion.

Abstract: A semiconductor laser device includes a laser diode provided on a semiconductor substrate, the laser diode including a first optical waveguide having a gain waveguide, a plurality of photodiodes, a first wavelength-selective filter having periodic transmission peaks, and a second wavelength-selective filter having periodic transmission peaks, the period of the transmission peaks of the second wavelength-selective filter being different from the period of the transmission peaks of the first wavelength-selective filter. Furthermore, two photodiodes among the plurality of photodiodes are optically coupled to the first optical waveguide through the first and second wavelength-selective filters, respectively.

Abstract: A semiconductor laser element 10 according to the present invention comprises a waveguide 12 of a high mesa type. And then such the waveguide 12 comprises an oblique end face 17 as an emitting facet that is different from a cleaved end face 16. And hence it becomes possible to reduce a reflection factor at the end face by making of such the oblique end face 17, and it becomes possible to design a direction of an emitting beam 21, that is to be emitting from the oblique end face 17, to be independent of that for the cleaved end face 16 as well. Moreover, the emitting beam 21 is designed to be emitting as vertical to the cleaved end face 16. And then therefore in a case where an emitting beam from a semiconductor optical device is designed to be coupled with such as an optical fiber or another waveguide or the like, it is not necessary to device such as that the semiconductor laser element 10 is required to be arranged at a sub mount by being inclined to be oblique or the like.

Abstract: A laser amplification arrangement comprising a laser medium for producing an amplified laser emission as output signal from a useful signal to be amplified and a pump source has a switching component for coupling the useful signal into the laser medium. Laser medium and switching component are formed and arranged so that a division of an input signal (ES) into the useful signal and a background signal is effected, the background signal being passed through the laser medium at a time immediately before and/or after the coupling-in of the useful signal to be amplified.

Abstract: The present invention relates to a mode-locker including a graphene and a laser pulse device. The mode-locker mode-locks a laser that propagates through a laser oscillation loop. The mode-locker includes: i) a core; ii) cladding that surrounds the core, wherein a groove is formed on a side of the cladding; and iii) a graphene layer that is located in the groove and is formed to be extended along a direction to be parallel to a transferring direction of the laser such that a laser pulse is formed by the interaction of the graphene and the field of the propagating laser mode.