An intra-cavity doubled OPS-laser has a laser-resonator including a birefringent filter (BRF) for coarse wavelength-selection, and an optically nonlinear (ONL) crystal arranged for type-II frequency-doubling and fine wavelength-selection. Laser-radiation circulates in the laser-resonator at one of a range of fundamental wavelengths dependent on the resonator length. The ONL crystal has a transmission peak-wavelength dependent on the crystal temperature. Reflection of circulating radiation from the BRF is monitored. The reflection is at a minimum when the ONL crystal transmission-peak wavelength is at the circulating radiation wavelength. The temperature of the ONL crystal is selectively varied to maintain the monitored reflection at about a minimum.

A laser power-supply device including a power-supply unit including a voltage input unit into which an AC voltage is inputted, a rectifier circuit, and a plurality of sub-switching regulator units, and a light-emitting unit, in which the plurality of sub-switching regulator units is connected in parallel to output of the rectifier circuit, the light-emitting unit includes a plurality of sub-light-emitting units, each of the sub-light-emitting units includes one light-emitting element row, a current is supplied to the one light-emitting element row from each of the plurality of sub-switching regulator units, and each of the sub-switching regulator units includes a switching circuit, a smoothing circuit, a current detection circuit that detects an output current, and a control circuit that controls the switching circuit on the basis of a current command value and the detected output current.

An optical module and a method of assembling the optical module are disclosed. The optical module comprises a laser unit, a modulator unit, and a detector unit mounted on respective thermo-electric coolers (TECs). The modulator unit, which is arranged on an optical axis of the first output port from which a modulated beam is output, modulates the continuous wave (CW) beam output from the laser unit. On the other hand, the laser unit and the detector unit are arranged on another optical axis of the second output port from which another CW beam is output. The method of assembling the optical module first aligns one of the first combination of the laser unit and the modulator unit with the first output port and the second combination of the laser unit and the detector unit, and then aligns another of the first combination and the second combination.

A tunable laser has a solid state laser medium having an optical gain region and generates coherent radiation through a facet. A lens collects the coherent radiation and generates a collimated light beam. Components of an external cavity include a reflective surface and an optical filter, the reflective surface reflecting the collimated beam back to the lens and the laser medium, the optical filter positioned between the reflective surface and the lens and having two surfaces with a thermally tunable optical transmission band within the optical gain region of the laser medium. The optical filter (1) transmits a predominant portion of the collimated beam at a desired wavelength of operation, and (2) specularly reflects a remaining portion of the collimated beam from each surface, the collimated beam being incident on the optical filter such that the reflected collimated beams propagate at a non-zero angle with respect to the incident collimated beam.

An optical module and a method of assembling the optical module are disclosed. The optical module comprises a laser unit, a modulator unit, and a detector unit mounted on respective thermo-electric coolers (TECs). The modulator unit, which is arranged on an optical axis of the first output port from which a modulated beam is output, modulates the continuous wave (CW) beam output from the laser unit. On the other hand, the laser unit and the detector unit are arranged on another optical axis of the second output port from which another CW beam is output. The method of assembling the optical module first aligns one of the first combination of the laser unit and the modulator unit with the first output port and the second combination of the laser unit and the detector unit, and then aligns another of the first combination and the second combination.

An optical system includes a laser cavity on a base. The laser cavity generates a light signal in response to application of an electrical current to the laser cavity. The system includes first electronics that apply a target level of the electrical current to the laser cavity so as to cause the laser cavity to generate the light signal. The light signal experiences mode hops at electrical current levels that shift to higher current levels in response to increasing laser operation times. A first one of the mode hops occurs at a first current level and a second one of the mode hops occurs at a second current level that is higher than the first current level. The system also includes a phase shifter that interacts with the laser cavity so as to shift the mode hops to lower current levels than occur in the absence of the phase shifter.

In a laser device, a different refractive index region 6B of a photonic crystal layer is arranged at a lattice point position of a square lattice. In the case where a plane shape of the different refractive index regions 6B is a nearly isosceles right triangle, two sides forming a right angle extend along longitudinal and horizontal lateral lines of the square lattice. A direction parallel to or vertical to an oblique side of the triangle and a direction of polarization in the periodic polarization inversion structure of a nonlinear optical crystal NL are the same.

An external resonator type laser device has an optical element that forms an external resonator with a semiconductor device by selecting and reflecting light of a specific wavelength range from light outputted from the semiconductor device; a supporting member formed of a material having a larger coefficient of linear expansion than the optical element; and a first mount interposed between the optical element and the supporting member, formed of a material having a coefficient of linear expansion closer to that of the optical element compared with that of the supporting member. The optical element is adhered to the first mount. The first mount is adhered to the supporting member by an adhesive having a Shore hardness of less than or equal to 65.

A laser power-supply device including a power-supply unit including a voltage input unit into which an AC voltage is inputted, a rectifier circuit, and a plurality of sub-switching regulator units, and a light-emitting unit, in which the plurality of sub-switching regulator units is connected in parallel to output of the rectifier circuit, the light-emitting unit includes a plurality of sub-light-emitting units, each of the sub-light-emitting units includes one light-emitting element row, a current is supplied to the one light-emitting element row from each of the plurality of sub-switching regulator units, and each of the sub-switching regulator units includes a switching circuit, a smoothing circuit, a current detection circuit that detects an output current, and a control circuit that controls the switching circuit on the basis of a current command value and the detected output current.

A semiconductor laser apparatus includes a semiconductor optical integrated device including a semiconductor laser array including a plurality of semiconductor laser elements, a semiconductor arrayed waveguide grating, made of a semiconductor, including an inputting slab waveguide connected to the plurality of the semiconductor laser elements, an array waveguide connected to the inputting slab waveguide and including a plurality of waveguides having different lengths from each other and arranged in a parallel manner, and an outputting slab waveguide connected to the array waveguide; a substrate on which the semiconductor laser array and the semiconductor arrayed waveguide grating are monolithically integrated; and an output facet outputting a laser light emitted from the semiconductor laserelements and including an output end of the outputting slab waveguide.