Abstract: A laser adjustment method includes a first adjustment step and a second adjustment step. In the first adjustment step, using a light detector detecting a second harmonic light, optical intensity and wavelength of the second harmonic light is detected and a first temperature adjuster is adjusted to adjust temperatures of a Nd:YVO4 crystal and a KTP crystal such that the detected wavelength of the second harmonic light approaches a desired wavelength and such that the optical intensity of the second harmonic light reaches at least a predetermined value. In the second adjustment step, after the first adjustment step, a temperature of an etalon is adjusted by a second temperature adjuster such that the detected wavelength of the second harmonic light approaches the desired wavelength and such that the optical intensity of the second harmonic light reaches at least a predetermined value.

Abstract: The invention relates to a laser diode (10) which has at least one active layer (12) which is arranged within a resonator (14) and is operatively connected to a outcoupling element (16), and further at least one contact layer (18) for coupling charge carriers into the active layer (12), wherein the resonator (14) comprises at least a first section (20) and a second section (22), wherein the second section (22) comprises a plurality of separate resistor elements (24) having a specific electrical resistivity greater than the specific electrical resistivity of the regions (26) between adjacent resistor elements (24), wherein a width (W3) of the resistor elements (24) along a longitudinal axis (X1) of the active layer (12) is less than 20 ?m, and a projection of the resistor elements (24) on the active layer (12) along the first axis (Z1) overlap with at least 10% of the active layer (12).

Abstract: A method of forming a laser including device is provided that in one embodiment includes providing a laser chip including at least one ridge structure that provides an alignment features. The method further includes bonding a type IV photonics chip to the laser chip, wherein a vertical alignment feature from the type IV photonics chip is inserted in a recess relative to the at least one ridge structure that provides the alignment features of the laser structure.

Abstract: A substrate including a photonic crystal has a compound semiconductor, dielectric layers, and a first semiconductor layer. The dielectric layers are provided on a surface of the compound semiconductor substrate and disposed at each grating point of a two-dimensional diffraction grating, each of the dielectric layers having an asymmetric shape in relation to at least one edge of the two-dimensional diffraction grating and having a refractive index lower than a refractive index of the compound semiconductor substrate. The first semiconductor layer includes a flat first face covering the dielectric layers and the surface of the compound semiconductor substrate, a layer constituting the first face containing a material capable of being lattice matched to a material constituting the compound semiconductor substrate.

Abstract: In various embodiments, a laser emitter such as a diode bar is cooled during operation via jets of cooling fluid formed by ports in a cooler on which the laser emitter is positioned. The jets strike an impingement surface of the cooler that is thermally coupled to the laser emitter but prevents direct contact between the cooling fluid and the laser emitter itself.

Abstract: The present disclosure relates to methods and apparatuses for providing optical radiation having improved rise/fall times and improved levels of leakage. One method for amplifying optical radiation includes an intermediate stage (220) having an intermediate active optical fiber (222), the intermediate active optical fiber and a final amplifying stage (230) including a final active optical fiber (232), and providing optical radiation to the input of the intermediate active optical fiber, wherein one or more final optical pump sources (235) are together in a low power state such that the optical radiation is substantially absorbed by the intermediate active optical fiber and such that substantially no optical radiation of the amplified wavelength is transmitted by the intermediate stage. The intermediate active optical fiber (222) can then be switched to a transmissive state by switching the final optical pump source(s) (235) to a high power state.

Abstract: A laser device provided with the function of predicting occurrence of condensation and preventing occurrence of condensation in advance. The laser device is provided with a controlling part calculating a reference temperature for judging whether a cooling water feed device may feed cooling water based on a temperature measured by a thermometer and a humidity measured by a hygrometer, and a comparing part comparing a reference temperature and a cooling water temperature. The cooling water feed device is configured to stop the feed of cooling water after a command for starting up the laser oscillator has been output and the cooling water temperature is lower than the reference temperature and to start or continue the feed of cooling water when the cooling water temperature is the reference temperature or more.

Abstract: To provide a two-dimensional photonic crystal surface emitting laser capable of improving characteristics of light to be emitted, in particular, optical output power.

Abstract: After forming a monolithically integrated device including a laser and a modulator on a semiconductor substrate, an anti-reflection coating layer is formed over the monolithically integrated device and the semiconductor substrate by an atomic layer deposition (ALD) process. The anti-reflection coating layer is lithographically patterned so that an anti-reflection coating is only present on exposed surfaces of the modulator. After forming an etch stop layer portion to protect the anti-reflection coating, a high reflection coating layer is formed over the etch stop layer, the laser and the semiconductor structure by ALD and lithographically patterned to provide a high reflection coating that is formed solely on a non-output facet of the laser.

Abstract: A system comprising drive circuitry configured to apply in a start-up phase a first drive current and then a second different drive current to a laser diode, the first drive current and second drive current being such that the laser diode is configured to provide a first optical output and a second optical output respectively. The system further comprising an optical sensor configured to provide a first sensor output corresponding to the first optical output of the laser diode and a second sensor output corresponding to the second optical output. The system further comprises a controller configured to use a value of the first drive current, a value of the second drive current, the first sensor output, the second sensor output and at least one supplied input value to provide control values for the drive circuitry to control an operating current of the laser diode, wherein the system is arranged to be used in a communication system wherein information is transmitted in at least one burst.

Abstract: Systems and methods are provided for imaging using complex lasers. In general, a complex laser may be used as an electromagnetic source for an imaging application. The use of a lower spatial coherence configured complex laser in imaging applications may advantageously mitigate coherent artifacts in imaging such as cross-talk and speckle and improve overall image quality. Imaging applications where a complex laser may be useful include both incoherent imaging applications, such as digital light projectors and traditional microscopy, and coherent imaging applications, such as optical coherence tomography (OCT) and holography. The systems and methods provided also enable controlling the degree of spatial coherence of a complex laser.

Abstract: A leakage light removal structure 70 is used to remove leakage light in an optical fiber 140 having a core 160, a cladding 162 having a refractive index lower than the core 160, and a covering material 164 having a refractive index higher than the cladding 162. The leakage light removal structure 70 has a fiber housing 72 that houses part of the optical fiber 140, a covering material extension portion 175 covering part of a whole circumference of the cladding 162 by extending part of the covering material 164 along a longitudinal direction of the optical fiber 140 within the fiber housing 72, and a cladding exposure portion 174 in which a portion of the whole circumference of the cladding 162 other than the covering material extension portion 175 is exposed within the fiber housing 72. The covering material 164 may be covered with a resin 76 having a refractive index not more than the refractive index of the covering material 164.

Abstract: A low voltage laser device having an active region configured for one or more selected wavelengths of light emissions.

Abstract: The invention relates to an external cavity tunable laser with dual beam outputs. The first laser cavity of the tunable laser comprises a first laser cavity mirror, a laser gain medium, an intracavity collimating lens, an active optical phase modulator, a tunable acousto-optic filter, a tunable Fabry-Perot tunable filter, a second reflection mirror all disposed inside a laser cavity sequentially, and a laser driver and control system. The laser cavity beam reflected by the first laser cavity mirror enters the tunable acousto-optic filter to generate a zeroth order diffracted beam as the first laser output beam. The laser cavity beam reflected by the second laser cavity mirror enters the tunable acousto-optic filter to generate a zeroth order diffracted beam as the second laser output beam. The tunable laser further comprises a wavelength locker outside the laser cavity.

Abstract: A surface emitting laser having a wide wavelength tunable band is provided. A surface emitting laser includes a first reflecting mirror (102); a second reflecting mirror (116); and an active layer (104) arranged between the first reflecting mirror (102) and the second reflecting mirror (116), a gap being formed between the second reflecting mirror (116) and the active layer (104), an oscillation wavelength being tunable. The second reflecting mirror (116) includes a beam (108) comprising a single-crystal semiconductor, and a dielectric multilayer film (110) supported by the beam (108), and the dielectric multilayer film (110) is arranged in an opening (118) formed in the beam (108).

Abstract: A vertical-cavity surface-emitting laser (VSCEL) and method for producing a VCSEL are described, the VCSEL including an undercut active region. The active region of the VCSEL is undercut relative to current-spreading layers of the VCSEL, such that a width of a tunnel junction of the VCSEL overgrown by a current spreading layer is less than a width of an active region of the VCSEL, and a width of the active region of the VCSEL is less than a width of the overgrown current-spreading layer, such that the VCSEL including the undercut active region is configured to transmit data at speeds greater than 25 gigabits/second.

Abstract: A method of forming a pair of edge-emitting lasers is provided. The method includes forming a mesa from a substrate, forming a cover layer on the substrate around the mesa, and forming a first barrier layer on each of opposite sidewalls of the mesa. The method further includes forming a quantum well layer on each of the barrier layers, forming a second barrier layer on each of the quantum well layers, and forming a cladding layer on each of the second barrier layers.

Abstract: In a semiconductor light emitting element provided with an active layer 4, a pair of cladding layers 2, 7 between which the active layer 4 is interposed, and a phase modulation layer 6 optically coupled to the active layer 4, the phase modulation layer 6 includes a base layer 6A and a plurality of different refractive index regions 6B having different refractive indices from the base layer 6A. When an XYZ orthogonal coordinate system having a thickness direction of the phase modulation layer 6 as a Z-axis direction is set and a square lattice of a virtual lattice constant a is set in an XY plane, each of the different refractive index regions 6B is disposed so that a centroid position G thereof is shifted from a lattice point position in a virtual square lattice by a distance r, and the distance r is 0<r?0.3a.

Abstract: The present invention relates to an artificial light system for modulating circadian rhythms, increasing vigilance and influencing light-associated psychological conditions such as seasonal affective disorder. The system of the invention comprises a source of a green and/or red light and a source of blue light both light sources being controlled by a computer to provide predetermined light conditions. More specifically, the computer is programmed to provide pulses of blue light and continuous or pulsed red light, to enhance the efficacy of blue light, reduce blue-light hazard and avoid stroboscopic effect.

Abstract: An optical semiconductor device includes: an n-type semiconductor substrate; an n-type cladding layer provided on the n-type semiconductor substrate; an active layer of a semiconductor laser provided on the n-type cladding layer; a waveguide layer of a waveguide provided on the n-type cladding layer and having a side facing a side of the active layer; a p-type cladding layer provided on the active layer and the waveguide layer; and a middle layer provided between the side of the active layer and the side of the waveguide layer, provided between the n-type cladding layer and the waveguide layer, not provided on the active layer, and having a band gap greater than a band gap of the waveguide layer.