Abstract: According to aspects of an embodiment of the disclosed subject matter, method and apparatus are disclose that may comprise adjusting a differential timing between gas discharges in the seed laser and amplifier laser for bandwidth control, based on the error signal, or for control of another laser operating parameter other than bandwidth, without utilizing any beam magnification control, or adjusting a differential timing between gas discharges in the seed laser and amplifier laser for bandwidth control, based on the error signal, or for control of another laser operating parameter other than bandwidth, while utilizing beam magnification control for other than bandwidth control, and adjusting a differential timing between gas discharges in the seed laser and amplifier laser for bandwidth control, based on the error signal, or for control of another laser operating parameter other than bandwidth, while utilizing beam magnification control for bandwidth control based on the error signal.

Abstract: This invention relates to a wavelength tunable light source, comprising a main resonator, having a first and a second mirrored end, defining an effective cavity length, i.e. an optical beam path length of a resonant mode of the cavity, an optical gain element, having a first and a second opposing end surface, said second surface being positioned within said main resonator, a mirror element constituting said second mirrored end, and a dispersive focusing resonator element, being positioned along a beam path between said second end surface and said mirror element, whereby said effective cavity length of said main resonator is arranged to be varied.

Abstract: A light source device includes: a laser light source emitting a laser beam of a prescribed wavelength; a nonlinear optical element, disposed facing a light emergence surface of the laser light sources which converts an emission wavelength of the laser beam emitted from the laser light source and causes the laser beam to emerge; a volume phase grating, disposed facing an emergence surface of the laser beam of the converted wavelength converted by the nonlinear optical element, which has formed in an interior thereof a Bragg grating structure which selectively reflects a laser beam of an emission wavelength; and a first dielectric multilayer, provided on a light emergence surface of the volume phase gratings which transmits the laser beam of the converted wavelength and reflects the laser beam of the emission wavelength.

Abstract: The invention describes the method and apparatus for enhanced efficiency in a laterally-coupled distributed feedback (LC-DFB) laser. In a device featuring the effective ridge design, lateral confinement of the guided optical modes is provided by a surface etched grating, which also serves as a DFB element of the laser. Coupling and quantum efficiency of such a LC-DFB laser both improve with an increase of the lateral mode order. In accordance with this invention, a dramatic enhancement of the laser efficiency is achievable by designing it to operate in one of the higher order modes, notably the first order mode, while all the other lateral modes, including the zero order mode, are suppressed through gain-loss discrimination.

Abstract: An optically pumped, surface-emitting semiconductor laser having a mode-selective apparatus (7) which is intended for suppression of predeterminable, higher resonator modes of the semiconductor laser. The mode-selective apparatus is arranged in the beam path of a pump beam source (2) of the surface-emitting semiconductor laser.

Abstract: Silica sol gel micro-lasers and methods of fabricating micro-lasers on a chip or a wafer. A silica sol gel micro-laser includes a silica sol gel optical micro-cavity, a substrate, and a support member or pillar that extends between the micro-cavity and the substrate. An outer surface or periphery of the micro-cavity extends beyond a top of the sol gel support member or is overhanging with respect to the underlying support member. Optical energy travels along an inner surface of the silica sol gel micro-cavity. Undoped silica sol gel micro-cavities can be used for Raman lasers. Sol gel micro-cavities can be doped with, for example, erbium, and can be used for erbium-doped micro-lasers that have ultra narrow line widths, for example, less than 100 Hz. Undoped and doped silica sol gel micro-lasers can have Q factors greater than 107.

Abstract: A single longitudinal-mode laser includes a first mirror and a second mirror that define a laser cavity therein that does not include a linear polarizer. A birefringent gain medium can generate a lasing light at a lasing wavelength along a light propagation direction in response to a pump light at a pumping wavelength. The birefringent gain medium has an optical axis substantially perpendicular to the light propagation direction. A first wave plate positioned between the first mirror and the birefringent gain medium is a quarter wave plate at the lasing wavelength and a whole wave plate at the pumping wavelength. A second wave plate is positioned between the birefringent gain medium and the second mirror. The first wave plat and the second wave plate in part produce a single longitudinal mode in the lasing light.

Abstract: A mode selection technique in a laser is described wherein a recess is formed in a surface of a waveguide in the laser. The recess provides a region of free space propagation within the waveguide which preferentially selects the lowest order mode. A mode selective RF excited CO2 slab laser, having a stable resonator in the waveguide dimension and a negative branch unstable resonator in the non-waveguide dimension, is constructed and the position and size of the recess is considered to provide low order mode selection.

Abstract: Systems and methods for stripping an optical mode from a semiconductor laser. A waveguide layer with multiple layers is included in the semiconductor laser and is typically arranged beneath the active region. The waveguide layer is configured to match the phase of the second order mode. The waveguide layer does not substantially match the primary optical mode of the laser. By matching the phase of the second order mode, the confinement of the second order mode is reduced and the second order mode strongly couples with the waveguide layer. The optical confinement of the primary mode is not substantially reduced. The side-mode suppression ratio is thereby improved by stripping the second order mode from the active region.

Abstract: A method and system of physically solving the charge, mass, and current density functions of excited-state atoms and atomic ions using Maxwell's equations and computing and rendering the nature of excited-state electrons using the solutions. The results can be displayed on visual or graphical media. The display can be static or dynamic such that electron spin and rotation motion can be displayed in an embodiment. The displayed information is useful to anticipate reactivity and physical properties. The insight into the nature of excited-state electrons can permit the solution and display of those of other atoms and atomic ions and provide utility to anticipate their reactivity and physical properties as well as spectral absorption and emission to lead to new optical materials and light sources.

Abstract: A single longitudinal-mode laser includes a first mirror and a second mirror that define a laser cavity therein that does not include a linear polarizer. A birefringent gain medium can generate a lasing light at a lasing wavelength along a light propagation direction in response to a pump light at a pumping wavelength. The birefringent gain medium has an optical axis substantially perpendicular to the light propagation direction. A first wave plate positioned between the first mirror and the birefringent gain medium is a quarter wave plate at the lasing wavelength and a whole wave plate at the pumping wavelength. A second wave plate is positioned between the birefringent gain medium and the second mirror. The first wave plat and the second wave plate in part produce a single longitudinal mode in the lasing light.

Abstract: A lasing method including the steps of providing a laser resonator; utilizing birefringence compensation in said resonator whereby said resonator is induced to operate in a Laguerre-Gaussian higher order mode; and utilizing polarized outcoupling of lasing energy at said higher order mode from said resonator. In the illustrative application, the laser resonator is a high-power, solid-state laser resonator. In the specific embodiment, the inventive method further includes the step of changing an outcoupling preference for a non-degenerate high-order Laguerre-Gaussian mode. In one embodiment, the step of changing outcoupling preference includes the step of changing an outcoupling polarization. In another embodiment, the step of changing outcoupling preference includes the step of changing an orientation of a roof edge of a prism in the laser resonator.

Abstract: A lasing method including the steps of providing a laser resonator; utilizing birefringence compensation in said resonator whereby said resonator is induced to operate in a Laguerre-Gaussian higher order mode; and utilizing polarized outcoupling of lasing energy at said higher order mode from said resonator. In the illustrative application, the laser resonator is a high-power, solid-state laser resonator. In the specific embodiment, the inventive method further includes the step of changing an outcoupling preference for a non-degenerate high-order Laguerre-Gaussian mode. In one embodiment, the step of changing outcoupling preference includes the step of changing an outcoupling polarization. In another embodiment, the step of changing outcoupling preference includes the step of changing an orientation of a roof edge of a prism in the laser resonator.

Abstract: A laser comprising: a resonator cavity defined by at least two reflectors, wherein the at least two reflectors are highly reflective at a plurality of fundamental wavelengths; a laser medium disposed in the resonator cavity capable of generating plurality of fundamental wavelengths; an optical pump source for energizing the laser medium, thereby causing laser light at the plurality of fundamental wavelengths to resonate in the resonator cavity simultaneously; and a nonlinear material located in said resonator cavity capable of simultaneously converting each of the plurality of wavelengths of laser light to generate converted laser light having a plurality of converted wavelengths, said converted wavelengths being derived from but different to the fundamental wavelengths; wherein the non-linear material is at least partially phase matched to nonlinearly convert the frequencies of each of the fundamental wavelengths simultaneously such that a plurality of converted wavelengths are able to be simultaneously gene

Abstract: Systems and methods for stripping an optical mode from a semiconductor laser. A waveguide layer is included in the semiconductor laser and is typically arranged beneath the active region. The waveguide layer is configured to match the phase of the second order mode. The waveguide layer does not substantially match the primary optical mode of the laser. By matching the phase of the second order mode, the confinement of the second order mode is reduced and the second order mode strongly couples with the waveguide layer. The optical confinement of the primary mode is not substantially reduced. The side-mode suppression ratio is thereby improved by stripping the second order mode from the active region.

Abstract: Various embodiments include modelocked fiber laser resonators that may be coupled with optical amplifiers. An isolator may separate the laser resonator from the amplifier, although certain embodiments exclude such an isolator. A reflective optical element on one end of the resonator having a relatively low reflectivity may be employed to couple light from the laser resonator to the amplifier. Enhanced pulse-width control may be provided with concatenated sections of both polarization-maintaining and non-polarization-maintaining fibers. Apodized fiber Bragg gratings and integrated fiber polarizers may be also be included in the laser cavity to assist in linearly polarizing the output of the cavity. Very short pulses with a large optical bandwidth may be obtained by matching the dispersion value of the fiber Bragg grating to the inverse of the dispersion of the intra-cavity fiber. Frequency comb sources may be constructed from such modelocked fiber oscillators.

Abstract: Current channels, blocking areas, or strips in a semiconductor laser are used to channel injected current into the antinodal region of the optical standing wave present in the optical cavity, while restricting the current flow to the nodal regions. Previous devices injected current into both the nodal and antinodal regions of the wave, which is fed by the population inversion created in the active region by the injected electrons and holes, but inversion created in the nodal regions is lost to fluorescence or supports the creation of undesirable competing longitudinal modes, causing inefficiency. Directing current to the antinodal regions where the electric field is at its maximum causes a selected longitudinal mode to preferentially oscillate regardless of where the longitudinal mode lies with respect to the gain curve. In one embodiment, exacting fabrication of the Fabry-Perot cavity correlates the current channels to antinodal regions, vis-a vis current blocking areas, strips or segmented layers.

Abstract: Semiconductor laser diodes, particularly high power ridge waveguide laser diodes, are often used in opto-electronics as so-called pump laser diodes for fiber amplifiers in optical communication lines. To provide the desired high power output and stability of such a laser diode and avoid degradation during use, the present invention concerns an improved design of such a device, the improvement concerns a method of suppressing the undesired first and higher order modes of the laser which consume energy and do not contribute to the optical output of the laser, thus reducing it's efficiency. This novel effect is provided by a structure comprising CIG—for Complex Index Guiding—elements on top of the laser diode, said CIG being established by fabricating CIG elements consisting of one or a plurality of layers and containing at least one layer which provides the optical absorption of undesired modes of the lasing wavelength.

Abstract: A surface-emitting type semiconductor laser includes: a lower mirror; an active layer formed above the lower mirror; and an upper mirror formed above the active layer, wherein the upper mirror includes a first region in which a plurality of holes are formed and a second region inside the first region in which no hole is formed, the second region is in a circular shape as viewed in a plan view, the circular shape has a radius with which an energy increasing rate in the active layer becomes positive with a lower-order mode and (becomes) negative with a higher-order mode, and the holes have a depth with which the energy increasing rate becomes positive with the lower-order mode, and becomes negative with the higher-order mode.

Abstract: A semiconductor laser device includes a substrate having a first surface and a second surface opposite to the first surface, an active region formed on the second surface of the substrate, a cladding layer formed on the active region, and an insulation region formed in the cladding layer to form on the second surface of the substrate a first laser region having a first size and a second laser region having a second size different from the first size. The first laser region is used for generating a first optical spectrum having a first laser mode channel space. The second laser region is used for generating a second optical spectrum having a second laser mode channel space. A combination of the first optical spectrum and the second optical spectrum forms a single mode laser. Without any gratings, the semiconductor laser device is easy to be fabricated and has a low fabrication cost.

Abstract: A multi-mode microlaser and a method for driving a multi-mode broad-area microlaser such as a multi-mode VCSEL is described such that the multi-mode microlaser shows an unexpected Gaussian-like far-field intensity distribution. The driving conditions are in general determined such that a strong reduction of the degree of spatial coherence occurs. For square pulsed driving current, these conditions are determined by the pulse duration pd and the pulse height ph. A Gaussian-like far-field intensity distribution is obtained for pulsed multi-mode broad area microlasers. The typical spatial coherence area corresponding with these driving conditions is substantially independent of the Fresnel number of the microlaser. Additionally, this partial spatial coherence can be tuned by changing the driving conditions, such as e.g. the pulse shape and length.

Abstract: The invention provides a method for 3D modeling of a three-dimensional tubular structure of an examination object from 2D projection images (D) of the structure taken from different projection directions. The method has the following steps: reconstruction of a 3D image from the 2D projection images (D); selection of at least one 3D central line point (MO) in the 3D image, said 3D central line point being located in the structure; segmentation of 3D central line points (M) of the structure in the 3D image; forward projection of the 3D central line points (M), which have been segmented in the 3D image, into 2D projection images (D?); determination of border points of the structure in the 2D projection images (D?) on the basis of 3D central line points (Z) that have been projected in; and back-projection of the border points from the 2D projection image (D?) into the 3D image.

Abstract: An external cavity laser includes a lasing cavity and an optically coupled feedback cavity having differently spaced resonant lasing and feedback mode frequencies. The lasing modes can be collectively or individually matched to selected feedback modes. For example, a current driving the lasing cavity can be adjusted to shift individual lasing modes into alignment with the selected feedback modes.

Abstract: The optical semiconductor device comprises a lower clad layer 12, optical waveguide layers 14, 16, 18 including an active layer for recombining the carriers. The upper clad layer 20 is mesa stripe configuration having a first mesa portion contacting the contact layer 22 and having a first width, and a second mesa portion having a second width larger than the first width. The first width, the second width and the thickness of the second mesa portion are set not to oscillate in the higher-order transverse mode.

Abstract: A laser system for generating self-starting few cycle laser pulses or widely tunable laser pulses is provided. The laser system includes a modelocked pump source that provides a pulsed pump signal. A gain medium receives the pulsed pump signal. A resonator structure includes the gain medium and a plurality of mirrors. The resonator structure defines a laser operated in a CW-modelocked regime generating few-cycle laser pulses having a duration less then 30 fs.

Abstract: A micro-cavity resonator including a micro-cavity capable of high and ultra-high Q values and a silicon substrate. Portions of the silicon substrate located below a periphery of the micro-cavity are removed to form a pillar, which supports the micro-cavity. Optical energy travels along an inner surface of the micro-cavity.

Abstract: A method for effective injection seeding is based on continuous wavelength sweeping for matching the injected seeds with one or more longitudinal mode(s) of the slave oscillator in every pump pulse. This is achieved through rapidly varying laser drive current resulted from RF modulation. Depending on the modulation parameters, the seed may be operated at quasi-CW or pulsed mode, with a narrow or broad bandwidth, for injection seeding of single longitudinal mode or multimode. The wavelength and bandwidth of the laser output can be tuned according to the needs. From pulse to pulse, the master-slave resonance may occur at different wavelengths upon cavity length fluctuations. Cavity length control via complicated feedback devices and phase locking schemes are consequently not required.

Abstract: A laser light source includes a light source section for outputting pulse laser light ?1, ?2 with a mutually identical repetition frequency, an optical amplification section for amplifying and outputting the pulse laser light ?1, ?2 output from the above light source section by means of a common optical amplification medium, an optical demultiplexing section for mutually demultiplexing pulse laser light ?1, ?2, an optical multiplexing section for multiplexing and outputting the pulse laser light ?1, ?2 demultiplexed in the above optical demultiplexing section, and an optical path length difference setting section for adjusting an optical path length difference between the pulse laser light ?1, ?2 in between the optical demultiplexing section and the optical multiplexing section.

Abstract: The present invention is to suppress deterioration of durability at the time when an optical component using a material optimized to be used in an optical path of a laser beam for performing reproduction/recording for a CD and a DVD is used in an optical head device using light sources including a blue semiconductor laser. A first transparent substrate 1 and a second transparent substrate 2 sandwich and hold therebetween a concave-convex portion 5 comprising a polymer liquid crystal, a filling adhesive 7 for filling the concave-convex, and a phase plate 6 having a retardation corresponding to ¼ of a wavelength used. An inorganic optical multilayer film 3 is formed on the whole surface of the first transparent substrate 1, on the side opposite to the concave-convex portion 5, and an inorganic optical multilayer film 4 is formed on the whole surface of the second transparent substrate 2, on the side opposite to the concave-convex portion 5.

Abstract: A mode-locked laser apparatus includes a resonator (laser cavity), a mode-locking device placed in the resonator, a solid-stated laser medium that is doped with Yb (ytterbium) and placed in the resonator and an excitation means for causing excitation light to enter the solid-state laser medium. In the mode-locked laser apparatus, light with an oscillation wavelength in a wavelength band on the longer wavelength side of the maximum peak wavelength in a fluorescence spectrum of the solid-state laser medium is used as output light.

Abstract: This utility model discloses a type of laser apparatus comprising a back mirror, a YV04 crystal, a Q-SW crystal, a front mirror, an optical pumping source, an optical fiber splice, a directional light-regulating lens and a laser head. The back mirror is a plano-concave lens, the incidence point of optical pumping source is deviated from the end surface center of YV04 crystal by 0-2 mm; under the back mirror there is a back mirror regulator; under the Q-SW crystal there is a Q-SW crystal regulator; above the front mirror there is a lens regulator; the laser head is located in front of the back mirror, the directional light-regulating lens is set in front of the laser head, the optical fiber splice is set in front of the directional light-regulating lens and under the lens there is a lens regulator.

Abstract: The present invention is a self-seeded laser diode. The laser diode obtains a gain by itself without using expansive erbium-doped fiber amplifiers. Hence, the cost is reduced and the system is simplified.

Abstract: An optical apparatus including a tunable master laser from which all or some of a beam is injected into at least one “slave ” laser having a cavity with an amplifier medium and a dynamic holographic medium that forms a self-adapted spectral filter to maintain oscillation of the slave laser at a wavelength imposed by the master laser during injection after injection has stopped.

Abstract: A pulsed laser for machining, has a mode switch, e.g. Q-switch device (15, 30, 40), in a resonant optical cavity (20) capable of supporting a given lasing mode, e.g. a transverse mode of oscillation when lasing action is started, arranged to induce, e.g. temporarily, a localized change, e.g. loss, in the cavity. The latter alters the given lasing mode, e.g. causes the oscillation to hop to a higher transverse mode temporarily, which on its hand may be extinguished by an aperture limiting diaphragm (5) or equivalent and subsequently reduce the induced loss temporarily, to return the oscillation to the given transverse mode and output the laser pulse. A modulator can be used for inducing the temporary loss for a first transverse lasing mode and extinguishing the higher transverse mode with a diaphragm. The induced loss can be over a localized area much smaller than the dimensions of a beam of the laser, so that a miniaturized modulator can be used. In this way pulsed operation may be achieved.

Abstract: A semiconductor laser includes a substrate made of InP, an active layer including a multiquantum well structure, which is formed in a width of 7 to 14 ?m on the substrate, and an n-type cladding layer made of InGaAsP and a p-type cladding layer made of InP, which are formed on the substrate with the active layer interposed therebetween. The semiconductor laser oscillates only in the fundamental lateral mode, and light emitted from an exit facet can be optically coupled with an external single mode optical fiber.

Abstract: A laser source is used in a geodesic device to improve the emission of laser light, in which the laser diodes emitting multimodal radiation are influenced by a mode-selective component such that the laser radiation emitted by the laser source has monomodal character. An edge emitter or a vertical semiconductor emitter with an external cavity, is hence used, in which a mode selective component is arranged, for example, a monomode fibre or resonator mirror, which has the effect of a mode-selective resonator construction. Components with negative dispersion can be used for pulse compression to compensate for the greater pulse duration generated by the lengthened cavity.

Abstract: A laser system, which is used in material processing to produce a radiation line of small width and uniform high intensity in the longitudinal direction, produces radiation that has different mode numbers M2 perpendicular to the propagation direction.

Abstract: The present invention concerns a design for an external cavity single mode laser wherein a short optical path length for the optical cavity (e.g., ˜3 to 25 mm) provides sufficient spacing of the longitudinal modes allowing a single wavelength selective element, such as a microfabricated etalon, to provide a single mode of operation, and optionally a selectable mode of operation.

Abstract: A surface emitting semiconductor laser includes a substrate, a lower reflective mirror formed on the substrate, an active layer formed on the lower reflective mirror, an upper reflective mirror formed on the active layer, an optical mode controlling layer formed between the lower reflective mirror and the upper reflective mirror, and a current confining layer formed between the lower reflective mirror and the upper reflective mirror. The active layer emits light. The upper reflective mirror forms a resonator between the lower reflective mirror and the upper reflective mirror. In the optical mode controlling layer, an opening is formed for selectively absorbing or reflecting off light that is emitted in the active layer. The optical mode controlling layer optically controls mode of laser light. The current confining layer confines current that is applied during driving.

Abstract: A Fabry-Perot laser and a micro-actuator are utilized to provide continuous tuning over a range of wavelengths.

Abstract: A multi-mode microlaser and a method for driving a multi-mode broad-area microlaser such as a multi-mode VCSEL is described such that the multi-mode microlaser shows an unexpected Gaussian-like far-field intensity distribution. The driving conditions are in general determined such that a strong reduction of the degree of spatial coherence occurs. For square pulsed driving current, these conditions are determined by the pulse duration pd and the pulse height ph. A Gaussian-like far-field intensity distribution is obtained for pulsed multi-mode broad area microlasers. The typical spatial coherence area corresponding with these driving conditions is substantially independent of the Fresnel number of the microlaser. Additionally, this partial spatial coherence can be tuned by changing the driving conditions, such as e.g. the pulse shape and length.

Abstract: There is provided a semiconductor device including a substrate and a semiconductor film deposited on the substrate, characterized in that the semiconductor film has a laterally grown crystal having an end with a surface projection height smaller than the thickness of the semiconductor film. There are also provided a semiconductor device fabrication method and apparatus utilizing a method and apparatus for fabricating the semiconductor device, that is capable of reducing a surface projection height or a ridge formed in a last region in repeating laser exposure in the SLS method, and a semiconductor device fabricated thereby.

Abstract: According to aspects of an embodiment of the disclosed subject matter, method and apparatus are disclose that ma y comprise adjusting a differential timing between gas discharges in the seed laser and amplifier laser for bandwidth control, based on the error signal, or for control of another laser operating parameter other than bandwidth, without utilizing any beam magnification control, or adjusting a differential timing between gas discharges in the seed laser and amplifier laser for bandwidth control, based on the error signal, or for control of another laser operating parameter other than bandwidth, while utilizing beam magnification control for other than bandwidth control, and adjusting a differential timing between gas discharges in the seed laser and amplifier laser for bandwidth control, based on the error signal, or for control of another laser operating parameter other than bandwidth, while utilizing beam magnification control for bandwidth control based on the error signal.

Abstract: A laser apparatus is disclosed. An optical element receives at least a part of laser light emitted from a laser generation source and generates interference fringes. Each of first and second two-divided detectors has two detectors arranged in the direction of which the interference fringes appear. Each of the detectors detects an amount of light of the interference fringes. These two-divided detectors are spaced apart for an odd-number multiple of nearly ¼ period of interference fringes and disposed on a plane perpendicular to an optical path of the interference fringes. Each of first and second calculation sections calculates a first difference signal of detection signals of two detectors of the two-divided detector. A selection section selects one of the first and second difference signals. A determination section determines a wavelength of the laser light corresponding to a value of the difference signal selected from the first and second difference signals.

Abstract: An optical spread spectrum communication system includes a tunable laser which sequentially outputs optical signals having different wavelengths. The laser produces a frequency spectrum having a plurality of closely spaced modes relative to optical frequencies. The system further includes an optical modulator and a frequency synthesizer. The frequency synthesizer controls the optical modulator to allow specific modes from the frequency spectrum to pass through. Additionally, the system includes a tunable filter and a phase locked loop (PLL) control circuit. The PLL control circuit controls the filter to select specific channels. The selection of the specific modes by the modulator and the selection of channels by the tunable filter are performed independent of each other and are based on randomly assigned codes generated in accordance with one or more algorithms.

Abstract: A surface-emitting type semiconductor laser includes a substrate, a first distributed Bragg reflection type mirror formed above the substrate, an active layer formed above the first mirror, a second distributed Bragg reflection type mirror formed above the active layer, and an insulation layer having an opening section that is formed in one of the first and second mirrors, wherein light generated from the active layer is emitted as a lower order mode laser beam lower order modeor a higher order mode laser beamhigher order mode, and the first mirror is formed with a number of pairs greater than the number of pairs of the second mirror such that the lower order mode laser beamlower order mode can be emitted in an upward direction of the substrate, and the opening section in the insulation layer is formed to have a size that enables the higher order mode laser beamhigher order mode to be emitted in a downward direction of the substrate.

Abstract: An inhomogeneous optical cavity is tuned by changing its shape, such as by changing reflection surface positions to change tilt angle, thickness, or both. Deformable components such as elastomer spacers can be connected so that, when deformed, they change relative positions of structures with light-reflective components such as mirrors, changing cavity shape. Electrodes can cause deformation, such as electrostatically, electromagnetically, or piezoelectrically, and can also be used to measure thicknesses of the cavity. The cavity can be tuned, for example, across a continuous spectrum, to a specific wavelength band, to a shape that increases or decreases the number of modes it has, to a series of transmission ranges each suitable for a respective light source, with a modulation that allows lock-in with photosensing for greater sensitivity, and so forth.

Abstract: Provided is a speckle reduction laser that emits laser light by resonating light generated from an active layer. The speckle reduction laser includes a mode changing unit having an electro-optical material layer disposed in a resonance path of the laser light, wherein a resonance mode of the laser light is changed when a voltage is applied to the electro-optical material layer.

Abstract: A light source device includes a light emitting section having at least one light emitting element for emitting a laser beam perpendicularly to an emission surface in laser oscillation, an external resonator for selectively returning light with a specific wavelength to the light emitting element, thereby causing the laser oscillation of the light emitting element with the specific wavelength, a base plate to which the light emitting section and the external resonator are fixed, and an optical element disposed and fixed on a light path of the laser beam between the light emitting element and the external resonator and distantly from the surface of the light emitting element, and for changing a proceeding direction of the laser beam.

Abstract: Disclosed is a fiber amplifier system including a gain fiber having a single-mode core containing dopant ions capable of producing stimulated emission of light at wavelength ?s when pumped with light of wavelength ?p. Absorbing ion filtering means is operatively associated with the gain fiber to alter the gain curve. If the absorbing ions are the same as the gain ions of the gain fiber, the system further includes means for preventing pump light from exciting the gain ions of the filtering means. The excitation prevention means may take the form of means for attenuating pump light. If the absorbing ions are different from the dopant ions of the gain fiber, such absorbing ions can be subjected to light at wavelength ?p, but they will remain unexcited. Such absorbing ions can be used to co-dope the gain fiber, or they can be incorporated into the core of a fiber that is in series with the gain fiber.