Abstract: A laser device includes a III-V heterostructure amplifying medium; a silicon optical waveguide having a coupling section facing a central portion of the amplifying medium, a propagation section and a first transition section between the coupling section and the propagation section; and a first and a second reflective structure allowing a Fabry-Perot type resonant cavity to be formed between them for the amplifying medium. The coupling section includes a refractive index disruption region provided with micro-reflectors designed to reduce the thickness and/or width of the coupling section. The first reflective structure is formed in a section of the waveguide with a first thickness. The second reflective structure is formed in a section of the waveguide, which has the first thickness and which is separated from the coupling section by a second transition section of the waveguide, the second transition section having a second thickness greater than the first thickness.

Abstract: Embodiments of the present disclosure relate to optical devices for augmented, virtual, and/or mixed reality applications. In one or more embodiments, an optical device metrology system is configured to measure a plurality of first metrics and one or more second metrics for optical devices, the one or more second metrics including a display leakage metric.

Abstract: Provided is a semiconductor laser element including: a resonator structure; and a first reflection film and a second reflection film provided on a non-emission end surface of the resonator structure and an emission end surface of the resonator structure, respectively. Reflectance R of the second reflection film at a gain wavelength satisfies the following relational expression: R1?R?R(Oc)×C where R1 is reflectance of the second reflection film when the resonator structure performs laser oscillation with power 1.4 times a minimum value of threshold power which is minimum power for the resonator structure to perform the laser oscillation, R(Oc) is reflectance of the external resonance mirror, and C is a ratio of light, which is reflected by the external resonance mirror and is incident in the resonator structure, to light which is reflected by the external resonance mirror.

Abstract: A laser device (100), comprising: a source of electromagnetic radiation (S) that comprises at least one reflecting surface (RS), said source (S) being configured to generate a light beam that follows an optical path (OPa; OP) external to said source (S); a dispersive stage (6) located outside said source (S) along said optical path (OP) of said light beam generated by said source (S), said dispersive stage (6) comprising at least one axis of reflection that forms an angle (?; cp) with said optical path (OPa; OP) of said light beam and being configured to reflect: at least a first spectral portion of said light beam generated by said source (S) towards said source (S); and a second spectral portion of said light generated by the source (S) along said axis of reflection, wherein said at least one reflecting surface (RS) and said dispersive stage (6) form at least one variable-length external optical cavity (RS, L, 6); at least one collimating lens (C) located along said optical path (OPa; OP) and configured to

Abstract: The present embodiment relates to a surface emitting type light-emitting element mainly including a nitride semiconductor and a layer for forming a resonance mode. The light-emitting element increases the optical confinement coefficient of a layer forming a resonance mode, includes an active layer, a phase modulation layer, and one or more high refractive index layers, and further includes, first and second cladding layers sandwiching the active layer, the phase modulation layer, and the high refractive index layer. The phase modulation layer includes a base layer and modified refractive index regions. The gravity centers of the modified refractive index regions are arranged on a straight line passing through each lattice point of a virtual square lattice and tilted with respect to the square lattice. The distance between the gravity center of each modified refractive index region and the lattice point is individually set according to the optical image.

Abstract: A photonic crystal surface-emitting laser includes a substrate, an n-type cladding layer, an active layer, an index matching layer and a photonic crystal structure. The n-type cladding layer is disposed over the substrate. The active layer is disposed over the n-type cladding layer. The index matching layer is disposed over the n-type cladding layer and is arranged around the active layer. The index matching layer is electrically insulating, and an effective refractive index of the index matching layer is substantially identical to an effective refractive index of the active layer. The photonic crystal structure is disposed over the active layer and the index matching layer.

Abstract: Embodiments of the present disclosure are directed to multi-wavelength laser generator may produce light with a frequency comb having equally spaced frequency lines. In various embodiments, the laser generator includes first, a semiconductor gain element is used to provide gain to the laser being generated. Second, a ring resonator filter, or ring filter, is used to select the wavelength comb spacing. Third, a narrow-band DBR or narrow-band mirror is used to select the number of wavelengths that lase. Fourth, a wide-band or narrow-band mirror is used to provide optical feedback and to form the optical cavity. Fifth, a phase tuner section is used to align the cavity modes with the ring resonances (i.e. the ring filter modes) in order to reduce or minimize the modal loss. Other embodiments may be described and/or claimed.

Abstract: A vertical cavity surface emitting laser (VCSEL) may include an active region (e.g., one or more quantum wells) and a chirped pattern reflector. The active region may be configured to be electrically pumped such that the active region generates light having a fundamental mode and a higher order mode. The chirped pattern reflector may include a first portion presenting to the active region as a first portion of an effective mirror having a concave shape and a second portion presenting to the active region as a second portion of the effective mirror having a convex shape.

Abstract: An optical microphone assembly including a substrate, an interferometric arrangement, a light source, and at least one photo detector. The interferometric arrangement includes a membrane and at least one diffractive optical element spaced from the membrane. The diffractive optical element(s) include a plurality of lines formed in or disposed on a surface of the substrate and arranged in a first pattern. The substrate includes one or more holes extending fully therethrough, the hole(s) arranged in a second pattern that is different from the first pattern. The light source is arranged to provide light to the interferometric arrangement such that first and second portions of the light propagate along respective, different first and second optical paths via the interferometric arrangement. An optical path difference between the first and second optical paths depends on a distance between the membrane and the diffractive optical element(s).

Abstract: Systems and methods are provided for an integrated chip. An integrated chip includes a package substrate including a plurality of first layers and a plurality of second layers, each second layer being disposed between a respective adjacent pair of the first layers. A transceiver unit is disposed above the package substrate. A waveguide unit including a plurality of waveguides having top and bottom walls formed in the first layers of the package substrate and sidewalls formed in the second layers of the package substrate.

Abstract: A photonic integrated circuit. In some embodiments, the photonic integrated circuit includes: a waveguide; and a waveguide facet, a first end of the waveguide being at the waveguide facet, a first angle being an angle between: the waveguide at the first end of the waveguide and the normal to the waveguide facet, the first angle being at least 5 degrees, a first section of the waveguide having a first end at the waveguide facet and a second end, the first section having: a curvature of less than 0.01/mm at the first end of the first section, a curvature of less than 0.01/mm at the second end of the first section, and a curvature of at least 0.1/mm at a point between the first end and the second end.

Abstract: The present disclosure relates to pretreating a magnetic recording head assembly for magnetic media drive. The magnetic recording head assembly comprises a slider having a media facing surface (MFS), a top surface disposed opposite the MFS, a trailing edge surface disposed adjacent to the top surface, and an optical grating disposed on the trailing edge surface. A vertical cavity surface emitting laser (VCSEL) device is mounted to the trailing edge surface of the slider. The VCSEL device is aligned with the optical grating. A magnetic recording head comprising a waveguide and a near field transducer (NFT) coupled to the waveguide is disposed on the trailing edge surface of the slider. The VCSEL device is capable of emitting a plurality of lasers that are phase coherent on to the optical grating. The optical grating is capable of directing the emitted lasers about 90 degrees to the waveguide.

Abstract: An output coupler can be used to couple multiple channels of light from a semiconductor waveguide to an optical fiber for wavelength division multiplexing. To couple light of a wide bandwidth (e.g., equal to or greater than 100 nm), two symmetrical gratings on two sides of a Fabry Perot cavity is used. The two symmetrical gratings are optimized to both reflect light for a Fabry Perot resonator and couple light out of the semiconductor waveguide.

Abstract: The grating layer of a surface emitting laser is divided into a first grating region and a second grating region along a horizontal direction. The second grating region is located at a middle area of the grating layer, while the first grating region is located in an outer peripheral area of the grating layer. Each of the first and second grating regions comprises a plurality of micro-grating structures. The grating period of the micro-grating structures in the first grating region is in accordance with the following mathematical formula: ? = m ? ? 2 ? n eff ; in addition, the grating period of the micro-grating structures in the second grating region is in accordance with the following mathematical formula: ? = o ? ? 2 ? n eff . Wherein ? is the length of grating period, ? is the wavelength of the laser light, neff is the equivalent refractive index of semiconductor waveguide, m=1, and o=2.

Abstract: An interferometric demodulation system for a large capacity fiber grating sensing network is provided by the present disclosure, comprising: a continuous light output end of the nanoscale wide-spectrum light source is connected to an input end of the pulse optical modulator, an output end of the reference grating is connected to an input end of the grating array sensing network, and a third communication end of the optical circulator is connected to an input end of the optical amplifier, an output end of the optical amplifier is connected to an input end of the Mach-Zehnder interferometer, three-channel signal output ends of the Mach-Zehnder interferometer are respectively connected to signal input ends corresponding to the embedded signal processor through the photoelectric converter, and the embedded signal processor controls the heating device to control a temperature of an any one of interference arms of the Mach-Zehnder interferometer.

Abstract: A 3D printer capable of adjusting a light transmission rate includes: a plate on which a forming material is disposed; a light source disposed above the plate and emitting light for curing the forming material; a course setting unit setting a processing course of the light emitted to the forming material; a beam shifting speed determination unit determining a beam shifting speed in each processing zone of the processing course set by the course setting unit; and a light transmission rate adjustment unit disposed between the forming material and the light source and adjusting a transmission rate of the light emitted to the forming material based on the beam shifting speed in each processing zone of the processing course.

Abstract: A fiber laser device includes a pumping light source, an amplifying fiber, an input side fiber fusion-spliced on an input side of the amplifying fiber and formed with a HR-FBG, an output side fiber fusion-spliced on an output side of the amplifying fiber and formed with an OC-FBG having a reflectivity smaller than that of the HR-FBG, an output end, and a mode filter, wherein the input side fiber or an intermediate fiber disposed between the amplifying fiber and the input side fiber is fusion-spliced with the amplifying fiber via a fusion splice portion, and at least a portion of the mode filter is disposed in a region between the fusion splice portion and a position separated from the fusion splice portion by a coherence length of beating caused by mode interference of signal light propagating in the amplifying fiber.

Abstract: A diffractive optical waveguide and a display device having the same are disclosed, which waveguide comprises a grating structure formed on a surface of a waveguide substrate. The grating structure comprises a plurality of grating lines arranged in a plane, which extend along a first direction in the plane and are arranged at a predetermined interval in a second direction perpendicular to the first direction; at least one sidewall of each grating line has a periodic structure along the first direction; and the grating structure is configured to diffract light incident thereon at a non-zero angle with respect to the plane, out of the plane through a predetermined diffraction order. The grating structure in the diffractive optical waveguide can be used to adjust diffraction efficiency on different angles and/or diffraction orders, thereby providing a new effective and flexible means for improving angular uniformity and/or coupling-out efficiency of the waveguide.

Abstract: The present invention provides a widely tunable, single mode emission semiconductor laser which comprises a semiconductor substrate, a first linear ridge waveguide which forms a first coupled cavity, and a second linear ridge waveguide which forms a second coupled cavity, with the first coupled cavity being separated from the second coupled cavity by a gap. The first and second coupled cavities comprise p-contacts and n-contacts for allowing laser currents I1, I2 to be injected into the first and second coupled cavities, respectively. The first and second coupled cavities comprise first and second heating resistors, respectively, for heating the first and second coupled cavities when heating currents H1, H2 are applied to the first and second heating resistors, respectively. A heating resistor is provided for heating the semiconductor substrate of the semiconductor laser so as to regulate the base temperature T of the chip (i.e., the semiconductor substrate).

Abstract: An apparatus for combining a plurality of coherent laser beams includes at least N?1 phase setting devices configured to set a respective phase (??n) of a respective one of the plurality of coherent laser beams, and a beam combination device configured to combine the plurality of coherent laser beams to form at least one combined laser beam. The beam combination device includes a microlens arrangement having at least two microlens arrays configured to form the at least one combined laser beam.

Abstract: The grating layer of a surface emitting laser is divided into a first grating region and a second grating region along a horizontal direction. The second grating region is located at a middle area of the grating layer, while the first grating region is located in an outer peripheral area of the grating layer. Each of the first and second grating regions comprises a plurality of micro-grating structures. The grating period of the micro-grating structures in the first grating region is in accordance with the following mathematical formula: ? = m ? ? 2 * n eff ; in addition, the grating period of the micro-grating structures in the second grating region is in accordance with the following mathematical formula: ? = o ? ? 2 * n eff . Wherein, ? is the length of grating period, ? is the wavelength of the laser light, neff is the equivalent refractive index of semiconductor waveguide, m=1, and o=2.

Abstract: A semiconductor optical device includes a substrate including a waveguide made of silicon and a semiconductor layer joined to the substrate so as to overlap the waveguide and including a diffraction grating formed of a first semiconductor layer and a second semiconductor layer having different refractive indices. The waveguide includes a bent portion and a plurality of straight portions that are connected to each other by the bent portion and that extend straight. The first semiconductor layer and the second semiconductor layer are each made of a compound semiconductor. The second semiconductor layer is embedded in the first semiconductor layer and includes a plurality of portions arranged in a direction in which the plurality of straight portions extend. The diffraction grating is positioned above the plurality of straight portions.

Abstract: An optoelectronic device includes a substrate and first thin film layers disposed on the substrate and patterned to define a vertical-cavity surface-emitting laser (VCSEL), which is configured to emit optical radiation along an optical axis perpendicular to the substrate. Second thin film layers are disposed over the first thin film layers and are patterned to define an optical modulator in which the optical radiation propagates in a direction parallel to the substrate, and an optical coupler configured to couple the optical radiation from the VCSEL into the optical modulator.

Abstract: An electrically pumped photonic-crystal surface-emitting laser, the epitaxy structure has a first mesa, the first mesa has multiple air holes and forming a photonic crystal structure, the epitaxy structure further has a second mesa, the second mesa and photonic crystal structure is facing the same direction; a first metal electrode arranged on the insulating layer, and covering the photonic crystal structure; a second metal electrode arranged on the second mesa and protruding out of the groove, making the first metal electrode and the second metal electrode face the same direction; and further make the first metal electrode connect to the first connecting metal and make the second metal electrode connect to the second connecting metal for making the photonic crystal structure become flip chip.

Abstract: A PIC has first, second and third elements fabricated on a common substrate. The first element includes a structure supporting efficient coupling of one or more free-space optical modes of incident light into one or more waveguide guided optical modes. The second element includes an on-chip interferometer having an input optically coupled to the waveguide guided optical modes; one or more arms; one or more outputs; and a phase tuner configured to change optical path length in one or more of the arms. The third element includes one or more light detecting structures optically coupled to the one or more outputs of the second element, such that variation in optical power in the one or more outputs is detected, allowing an assessment of coherence characterizing the light incident on the first element of the PIC to be provided.

Abstract: An apparatus for displaying an image, including: an input image node configured to provide at least a first and a second image modulated lights; and a holographic waveguide device configured to propagate the at least one of the first and second image modulated lights in at least a first direction. The holographic waveguide device includes: at least a first and second interspersed multiplicities of grating elements disposed in at least one layer, the first and second grating elements having respectively a first and a second prescriptions. The first and second multiplicity of grating elements are configured to deflect respectively the first and second image modulated lights out of the at least one layer into respectively a first and a second multiplicities of output rays forming respectively a first and second FOV tiles.

Abstract: Disclosed is a Vernier effect DBR laser that has uniform laser injection current pumping along the length of the laser. The laser can include one or more tuning elements, separate from the laser injection element, and these tuning elements can be used to control the temperature or modal refractive index of one or more sections of the laser. The refractive indices of each diffraction grating can be directly controlled by temperature changes, electro optic effects, or other means through the one or more tuning elements. With direct control of the temperature and/or refractive indices of the diffraction gratings, the uniformly pumped Vernier effect DBR laser can be capable of a wider tuning range. Additionally, uniform pumping of the laser through a single electrode can reduce or eliminate interfacial reflections caused by, for example, gaps between metal contacts atop the laser ridge, which can minimize multi-mode operation and mode hopping.

Abstract: Described herein is a two chip photonic device (e.g., a hybrid master oscillator power amplifier (MOPA)) where a gain region and optical amplifier region are formed on a III-V chip and a variable reflector (which in combination with the gain region forms a laser cavity) is formed on a different semiconductor chip that includes silicon, silicon nitride, lithium niobate, or the like. Sides of the two chips are disposed in a facing relationship so that optical signals can transfer between the gain region, the variable reflector, and the optical amplifier.

Abstract: A system, method, and apparatus for continuous seed laser pulses supplied to a CW pumped pre-amplifier and/or power-amplifier chain comprises an optical modulator configured to impress pulse signals on an optical signal, a waveform generator configured to establish a structure of the optical signal, and a keep-alive circuit that generates a continuous electrical pulse pattern provided to the optical modulator, wherein the system provides a continuous seed laser pulse structure.

Abstract: The invention provides a wavelength conversion device and a projection device including the same. The wavelength conversion device includes a substrate, a reflective layer, and a wavelength conversion layer. The reflective layer has different thicknesses in a radial direction of the substrate. The invention further provides another wavelength conversion device and another projection device including the same. In the wavelength conversion device, the reflective layer includes a first colloid and reflective particles distributed in the first colloid. The reflective layer includes an inner reflective layer, a central reflective layer and an outer reflective layer. The concentration of the reflective particles in the central reflective layer is different from the concentration of the reflective particles in the inner reflective layer and the concentration of the reflective particles in the outer reflective layer.

Abstract: A tunable wavelength laser comprising a laser cavity formed by a broadband mirror and a comb mirror. The laser cavity comprising a gain region. The laser cavity is configured such that a non-integer number of cavity modes of the laser cavity are between two consecutive reflection peaks of the comb mirror.

Abstract: A semiconductor laser diode includes a semiconductor body having an emitter region; and a first connection element that electrically contacts the semiconductor body in the emitter region, wherein the semiconductor body is in contact with the first connection element in the emitter region, and at least in places in the emitter region, the semiconductor body has a structuring that enlarges a contact area between the semiconductor body and the first connection element.

Abstract: An optical waveguide element includes an optical waveguide which is formed on one surface of a substrate, an incidence part for light to be incident on the optical waveguide or an emission part for emitting light from the optical waveguide which is disposed in an end portion of the substrate, and a dielectric film which is formed on the optical waveguide of at least one of the incidence part and the emission part, and the vicinity thereof. Regarding the dielectric film, dielectric films including a dielectric film formed of a first material having an index of refraction higher than an index of refraction of the substrate and a dielectric film formed of a second material having an index of refraction lower than the index of refraction of the substrate are alternately laminated.

Abstract: A grating coupler having first and second ends for coupling a light beam to a waveguide of a chip includes a substrate configured to receive the light beam from the first end and transmit the light beam through the second end, the substrate having a first refractive index n1, a grating structure having curved grating lines arranged on the substrate, the grating structure having a second refractive index n1, wherein the curved grating lines have line width w and height d and are arranged by a pitch ?, wherein the second refractive index n2 is less than first refractive index n1, and a cladding layer configured to cover the grating structure, wherein the cladding layer has a third refractive index n3.

Abstract: A light source device according to an embodiment is used with a light guide member and a wavelength converting member, and includes a light-emitting element, a light sensor, and a driving unit. The light-emitting element radiates a light beam to be incident on a first end of the light guide member by being supplied with a drive current. The light sensor detects signal light, which has been incident on a second end of the light guide member and transmitted to the first end. The driving unit supplies the drive current to the light-emitting element and controls the drive current based on a result of detection of the signal light.

Abstract: An example system includes a grating coupled laser, a laser optical interposer (LOI), an optical isolator, and a light redirector. The grating coupled laser includes a laser cavity and a transmit grating optically coupled to the laser cavity. The transmit grating is configured to diffract light emitted by the laser cavity out of the grating coupled laser. The LOI includes an LOI waveguide with an input end and an output end. The optical isolator is positioned between the surface coupled edge emitting laser and the LOI. The light redirector is positioned to redirect the light, after the light passes through the optical isolator, into the LOI waveguide of the LOI.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for tuning photonic device performance. In one aspect, a method includes receiving an initial photonic device configuration including multiple coupling structures and multiple photonic components. A first amount of light coupling between a first photonic component and a second photonic component of the multiple photonic components is received, which depends upon a subset of the coupling structures that are located between the first photonic component and the second photonic component. One or more coupling structures of the subset of coupling structures located between the first photonic component and the second photonic component are determined to be removed to cause the light coupling between the first photonic component and the second photonic component to change from the first amount of coupling to a target amount of coupling.

Abstract: An endoscope system of the present invention includes: a first illumination unit that emits first illumination light for imaging two sets of image information about a subject at different depths; a second illumination unit that emits second illumination light having a wide band covering a visible band from a position different from the position of the first illumination light; an imaging unit that images a first illumination image and a second illumination image of the subject that is illuminated with the first illumination light and the second illumination light; a separation processing unit that separates the two sets of image information from the first illumination image; and a separated-image generating unit that generates two separated images by processing the second illumination image using the two sets of image information.

Abstract: Disclosed is a broadband objective lens and a method of manufacturing the objective lens. The objective lens includes a plurality of lenses, and each of the lenses includes a coating layer on which a nanopattern is formed.

Abstract: A laser system including: A. a laser apparatus configured to output a pulse laser beam; B. an optical pulse stretcher including a delay optical path for expanding a pulse width of the pulse laser beam; and C. a phase optical element included in the delay optical path and having a function of spatially and randomly shifting a phase of the pulse laser beam. The phase optical element includes a plurality of types of cells providing different amounts of phase shift to the pulse laser beam and arranged irregularly in any direction.

Abstract: A vehicle lamp (1) includes a light source (30) that emits pieces of laser light (LR, LG, LB) having different wavelengths in a time division manner, and a plurality of diffraction gratings (43R, 43G, 43B) corresponding to the pieces of laser light (LR, LG, LB) of the wavelengths, respectively. The laser light (LR, LG, LB) of the wavelengths emitted from the light source (30) are incident on the diffraction gratings (43R, 43G, 43B) corresponding to the laser light (LR, LG, LB), and regions irradiated with light (DLR, DLG, DLB) emitted from the diffraction grating (43R, 43G, 43B) overlap with each other.

Abstract: The invention relates to a method for the two-dimensional reconstruction of wave fronts (104) of light for use in an optical system (100) comprising: measuring the distribution function of the light intensity in at least two images at different optical planes (101, 102) having an optical path difference. In particular this method is suitable for probing the tomographical distribution of wave fronts of electromagnetic fields with an image detector, e.g. any standard two-dimensional camera.

Abstract: Forming a light pulse having a plurality of time-dependent frequency components such as a chirped light pulse or a light pulse group and superposing reflected light from different portions of an optical fiber allows detection of changes in effective optical path differences due to physical parameters in the environment of the optical fiber by sensing the optical interference pattern of each light frequency and wavelength. The development of a plurality of interference patterns from each light pulse provides sufficient information for robust demodulation by known methods to produce signals having good fidelity to variations in the physical parameters of interest, particularly vibrations and acoustic waves. The location of the measured physical parameter along the optical fiber can be determined from the time difference between injecting the light pulse and detection of a reflection or Rayleigh backscattering and diffraction index of the optical fiber.

Abstract: Provided is a laser device that includes a laser chamber in which a pair of discharge electrodes are disposed; a line narrowing optical system including a grating disposed in a position outside the laser chamber; a beam expander optical system that increases a diameter of a light beam, outputted from the laser chamber and traveling toward the grating, in a first direction parallel to a discharge direction between the discharge electrodes and in a second direction orthogonal to the discharge direction; and a holding platform that is formed as a component separate from the laser chamber and the grating, holds the beam expander optical system, and forms along with the beam expander optical system a beam expander unit.

Abstract: A grating coupler having first and second ends for coupling a light beam to a waveguide of a chip includes a substrate configured to receive the light beam from the first end and transmit the light beam through the second end, the substrate having a first refractive index n1, a grating structure having curved grating lines arranged on the substrate, the grating structure having a second refractive index n1, wherein the curved grating lines have line width w and height d and are arranged by a pitch ?, wherein the second refractive index n2 is less than first refractive index n1, and a cladding layer configured to cover the grating structure, wherein the cladding layer has a third refractive index n3.

Abstract: An edge-emitting laser includes an active gain section and a reflector section optically coupled to the active gain section. The active gain section is configured to amplify an optical power of light across a wavelength range. The reflector section is configured to selectively reflect light of a selected wavelength within the wavelength range. The selected wavelength is tunable via high-frequency index modulation of the reflector section. The active gain section and the reflector section collectively form an optical cavity configured to lase coherent light in the selected wavelength.

Abstract: Microwave-to-optical transducers in an optical ring resonator having intracavity grating to split a single resonance order are provided. In one aspect, a microwave-to-optical transducer includes: an optical ring resonator with intracavity grating; and a microwave signal waveguide optically coupled to the optical ring resonator with the intracavity grating. Microwave-to-optical transducers having multiple pump photon optical ring resonators and multiple signal photon optical ring resonators optically coupled to the optical ring resonator with the intracavity grating are also provided, as is a method of forming a microwave-to-optical transducer, and a method for microwave-optical transduction.

Abstract: A semiconductor light-emitting device includes an active layer including quantum dots, a diffraction grating, a low-reflectance film disposed at a light-emitting end of the active layer, and a high-reflectance film disposed at another end of the active layer and having an optical reflectance higher than an optical reflectance of the low-reflectance film.

Abstract: A distributed acoustic sensing (DAS) system has a coherent light source device that repeatedly sends a coherent interrogating light pattern (CILP) into an optical sensing fiber during a measurement duration that is equal to or greater than a down-up travel time of the optical sensing fiber. The CILP is one of a plurality of patterns composed of coherent carrier light. A detection device detects backscattered light in the optical sensing fiber in response to the CILP and generates a signal indicative of the detected backscattered light. An evaluation device analyses the signal. Each CILP has similar physical properties that render the light patterns indistinguishable by comparing physical properties of the backscattered light responsive to at least two successive interrogating light patterns as detected. The coherent light source device can change the time between successively sent interrogating light patterns after the passing of at least one measurement time duration.

Abstract: The invention relates to an inspection device for masks for semiconductor lithography, comprising an imaging device for imaging a mask, and an image recording device, wherein one or more correction bodies which exhibit a dispersive behavior for at least one subrange of the illumination radiation used for the imaging are arranged in the light path between the mask and the image recording device. The invention furthermore relates to a method for taking account of longitudinal chromatic aberrations in inspection devices for masks, comprising the following steps: recording a specific number of images having differently defocused positions, and selecting a subset of the images and simulating a longitudinal chromatic aberration of a projection exposure apparatus.