Abstract: A fiber optic voltage conditioner, and method therefor, generally relate to voltage conditioning. In such a fiber optic voltage conditioner, there is a laser, and an optical circulator is coupled to receive a light signal from the laser. A controller is coupled to the laser and is configured to generate first control information for wavelength-drift control of the laser. A data acquisition module is coupled to the controller and is configured to generate second control information for the controller for adjustment of the first control information. A photodetector is coupled to the optical circulator to receive a returned optical signal and is coupled to the data acquisition module to provide an analog output signal thereto. The photodetector is configured to generate the analog output signal responsive to the returned optical signal. The data acquisition module is configured to generate the second control information using the analog output signal.

Abstract: Embodiments relate to an optical sensor for sensing hydrogen gas, which includes an optical fiber through which light moves; a ferrule formed at one end of the optical fiber to surround the optical fiber; and a sensor module configured to form an interference wave according to a Fabry-Perot interferometer with respect to light that moves through the optical fiber, wherein the sensor module includes a sensing material that expands and contracts by reacting with hydrogen gas, and spectrum periodicity of the interference wave changes according to a volume change of the sensing material, and a hydrogen gas detection system including the optical sensor.

Abstract: A sensor is provided for measuring a flow of a fluid in a physiological environment, such as within a vessel of a human or animal subject. The sensor comprises an interrogation light guide extending from a proximal end to a distal end of the sensor. The interrogation light guide is configured to transmit interrogation light to, and receive reflected interrogation light from, the distal end of the sensor. The sensor further comprises an excitation light guide configured to transmit excitation light to the distal end of the sensor. The excitation light is provided for heating the fluid (directly or indirectly). The sensor further comprises a sensing element located at the distal end of the sensor. The sensing element comprises at least two etalons for reflecting interrogation light back along the interrogation light guide towards the proximal end of the sensor. Each etalon has a respective optical path length and further has at least one reflective surface external to the interrogation light guide.

Abstract: Disclosed is a measurement system using a fiber Bragg grating sensor, which includes a sensing unit including a plurality of dynamic sensors and static sensors using fiber Bragg gratings to detect mutually different physical quantities to be measured, an optical meter configured to measure each physical quantity by simultaneously processing data output from the plurality of dynamic sensors and static sensors in real time, and a server configured to store and manage the data measured by the optical meter. Mutually different physical quantities are measured by simultaneously processing the data output from the plurality of dynamic sensors and static sensors in real time by using one optical meter.

Abstract: A system and method for demodulation of a fiber optic interferometric sensor are provided. Another aspect pertains to a system and method employing a single laser to generate multiple quadratic wavelengths to demodulate fiber optic interferometric sensors with approximately sinusoidal fringes. Yet another aspect of the present system and method uses a single frequency laser which is split into multiple paths using a fiber optic coupler, with one path including an intensity modulator and another path including an acousto-optic modulator, whereafter the paths are recombined into a fiber which leads to an interferometric sensor, and the light reflected from the sensor is then directed to a photodetector. A further aspect employs a single frequency laser which is split into multiple paths, with the light in the paths being modulated at different frequencies, whereafter the paths are recombined into a fiber which leads to an interferometric sensor.

Abstract: Various methods and systems for improved anterior segment optical coherence tomography (OCT) imaging are described. One example method includes collecting a set of B-scans over a range of different transverse locations on the cornea, segmenting each B-scan to identify an anterior corneal layer and an outer edge of Bowman's layer, calculating thickness values for each B-scan by computing the distance from the anterior corneal layer to the outer edge of the Bowman's layer, combining the thickness values from the B-scans to create a polar epithelial thickness map, converting the polar epithelial thickness map to a Cartesian epithelial thickness map using a fitting method, and storing or displaying the Cartesian epithelial thickness map or information derived from the Cartesian epithelial thickness map.

Abstract: A Michelson interference optical fiber temperature sensor for detecting fringe contrast change is provided. It includes a light source, an optical fiber coupler connected to a first optical fiber and a second optical fiber, a coarse wavelength division multiplexer, a first photodetector, a second photodetector, a display device, and a processing circuit connected to the display device. The light source, optical fiber coupler and coarse wavelength division multiplexer are connected sequentially in that order. The coarse wavelength division multiplexer is connected to the first photodetector and the second photodetector individually. The first photodetector and the second photodetector are connected to the processing circuit. An end of the first optical fiber or the second optical fiber facing away from the optical fiber coupler is connected to a semiconductor. It has advantages of simple and fast manufacturing process, safe and reliable sensor, stable signal, low cost, high sensitivity and high precision.

Abstract: A fiber optic voltage conditioner, and method therefor, generally relate to voltage conditioning. In such a fiber optic voltage conditioner, there is a laser, and an optical circulator is coupled to receive a light signal from the laser. A controller is coupled to the laser and is configured to generate first control information for wavelength-drift control of the laser. A data acquisition module is coupled to the controller and is configured to generate second control information for the controller for adjustment of the first control information. A photodetector is coupled to the optical circulator to receive a returned optical signal and is coupled to the data acquisition module to provide an analog output signal thereto. The photodetector is configured to generate the analog output signal responsive to the returned optical signal. The data acquisition module is configured to generate the second control information using the analog output signal.

Abstract: A passive microscopic Fabry-Pérot Interferometer (FPI) pressure sensor includes an optical fiber and a three-dimensional microscopic optical enclosure. The three-dimensional microscopic optical enclosure includes tubular side walls having lateral pleated corrugations and attached to a cleaved tip of the optical fiber to receive a light signal. An optically reflecting end wall is distally engaged to the tubular side walls to enclose a trapped quantity of gas that longitudinally positions the optically reflecting end wall in relation to ambient air pressure, changing a distance traveled by a light signal reflected back through the optical fiber.

Abstract: A passive microscopic Fabry-Pérot Interferometer (FPI) sensor includes a three-dimensional microscopic optical structure formed on a cleaved tip of the optical fighter using a two-photon polymerization process on a photosensitive polymer by a three-dimensional micromachining device. The three-dimensional microscopic optical structure having a hinged optical layer pivotally connected to a distal portion of a suspended structure. A reflective layer is deposited on a mirror surface of the hinged optical layer while in an open position. The hinged optical layer is subsequently positioned in the closed position to align the mirror surface to at least partially reflect a light signal back through the optical fiber.

Abstract: A high-performance distributed fiber sensing system based on EHz ultrafast pulse scanning. During testing of a disturbance signal, an internally frequency converted pulse light emitted by an EHz ultrafast pulse scanning laser enters a sensing fiber after passing through a circulator, and a backward Rayleigh scattering signal transmitted by the sensing fiber enters an unbalanced Michelson interferometer after passing through a coupler. By designing an arm length difference between two interference arms, interferences sequentially occur for the backward Rayleigh scattering light at a position where lengths of two adjacent arms differ. A signal received after passing through the unbalanced Michelson interferometer includes a phase difference signal caused by an external disturbance signal in the sensing fiber.

Abstract: There is provided a system and a method for extracting data traffic from an optical communication fiber by extracting a portion of the optical signal(s) propagating in the optical communication fiber, carrying the extracted signal over an optical fiber, amplifying the extracted optical signal and filtering the amplified signal to select one channel carrying data traffic. The optically-carried data traffic may then be input to an optical communication transceiver for converting the optically-carried data traffic into electrical data traffic, which carried data can be analyzed for data traffic monitoring applications.

Abstract: A weak value amplification (WVA) Corolis vibratory gyroscope (CVG) is provided for measuring angular rate. The WVA CVG includes a vibratory structure that induces a deflection; an optical weak value amplifier that amplifies the deflection as an amplified signal; and a weak value detector to measure the amplified signal to determine the angular rate. Further exemplary embodiments provide first and second plates, a laser, a polarizing filter, a beam-splitter, left and right mirrors, a half-wave plate, a retarder and a detector. The laser emits an emission beam of photons. The polarizing filter polarizes the emission beam. The beam-splitter divides the beam into left and right beams reflected by the left and right mirrors. The retarder imposes a phase difference between the left and right beams. The detector measures the left and right beams.

Abstract: Certain aspects of the present disclosure provide a local oscillator (LO) for wireless communication. In some examples, the LO is configured to generate an LO signal by inverting, by a first inverter, a first signal to generate a second signal having a first frequency, the first signal being an oscillating signal. In some examples, the LO is configured to control, using a third signal having a second frequency, a first switch receiving the second signal. In some examples, the LO is configured to control, using a fourth signal having the second frequency, a second switch receiving the second signal, wherein the fourth signal is a complement of the third signal and wherein the second frequency is one-half the first frequency.

Abstract: A non-contact photoacoustic spectrophotometry system is configured to measure an absorption spectrum of a material. The system includes a modulated light source such as tunable pulsed laser that generates laser pulses to produce photoacoustic signals in the material. A non-contact detector monitors the surface of the container for the material. The detector includes a second light source, such as a continuous wave laser, focused on the surface of the container, and transmits reflected light to an interferometer, for example, a Sagnac interferometer. The interferometer produces an interference signal from the received light that is proportional to the acoustic pressure, which is transmitted to a computer to calculate an absorption coefficient. Using a plurality of wavelengths from the tunable pulsed laser, an absorption spectrum may be generated.

Abstract: According to one embodiment, an ultrasound diagnostic apparatus comprises processing circuitry. The processing circuitry sets one of wavelengths of a plurality of light sources as a reference wavelength, normalize an intensity of light having a wavelength other than the reference wavelength, which is detected by a pair of each light irradiation unit and each optical detector, with an intensity of light having the reference wavelength, calculate a first value for each pair by nonlinear enhancement correction of a normalized light intensity, calculate a second value for the each pair by nonlinear reduction correction of an intensity of light having the reference wavelength detected by the each pair, and calculate an evaluation value based on a value obtained by multiplication of the first value and the second value for the each pair.

Abstract: A system for determining a calibrated spectral measurement includes a tunable Fabry-Perot etalon, a detector, and a processor. The tunable Fabry-Perot etalon has a settable gap. The detector measures light intensity transmitted through the tunable Fabry-Perot etalon. The processor is configured to determine the calibrated spectral measurement. The calibrated spectral measurement is based at least in part on a measurement set of detected light intensities for a plurality of settable gaps and a reconstruction matrix. The reconstruction matrix is based at least in part on calibration measurements using multiple source wavelengths and multiple settable gaps.

Abstract: A method of monitoring a structure for stresses or cracks. A single mode optical fiber is adhered to a structure. The single mode optical fiber includes a first optical cavity. The first optical cavity includes two fiber Bragg gratings with a distance therebetween. The first optical cavity includes a resonance. A frequency shift of the resonance of the first optical cavity is measured with a frequency discriminator. An acoustic emission from the structure is detected based on the frequency shift.

Abstract: A method for limiting impulse noise in a radio signal, in particular in the FM band, that is multiplexed and intended to be received by an FM receiver that is for example located on-board a vehicle. The method includes detecting impulse noise by way of a calculation of a score IND, for a sequence of successive samples of the demodulated radio signal FM MPX, while taking into the account, on the one hand, a capacity to detect a drop in the modulus of the ratio I/Q, which is dependent in particular on data derived from a sensor level, and, on the other hand, a capacity to detect high-frequency noise, which in particular depends on data derived from a sensor modulation.

Abstract: A compact and portable apparatus for measuring properties of objects utilizing a fiber optic Sagnac interferometer is enabled. The fiber optic Sagnac interferometer may be a double differential Sagnac interferometer. The interferometer core may be implemented with fiber optic components including polarization maintaining optical fiber, and by utilizing an auto-balanced avalanche photodetector. An optical switch may be incorporated to maintain relatively low average probe signal power while allowing optimal peak probe signal power. The compact and portable apparatus may be configured to measure ultrasonic vibrations, a displacement of an object surface in response to ultrasonic vibrations, and/or a vibration speed of the object surface. A wideband light source may be amplified and stabilized. A sensor head of the interferometer may incorporate a collimator adjustable to block a central portion of the projected probe beam thereby at least in part enabling in-plane and out-of-plane measurements.

Abstract: A flexible optical measuring device comprises an optical distance measuring module, an optical fiber adapter and an optical coupling module. The optical distance measuring module comprises a light source, an optical receiver and a computing unit. The optical fiber adapter is disposed and connected between the optical distance measuring module and the optical coupling module. The optical coupling module comprises a first optical fiber, a two-in-one optical coupler, a detector and a second optical fiber. A measuring beam is emitted from the light source and reaches the detector. The measuring beam then passes through the detector to the object and forms a reflected beam which is reflected back to the detector, then enters the second optical fiber and passes through the optical receiver and the optical receiver outputs a measurement signal. The computing unit calculates the distance between the object and a terminal of the detector accordingly.

Abstract: A displacement sensor has a graded index multi-mode fiber with a length that is an odd multiple of a quarter pitch length of the graded index multi-mode fiber and a single-mode optical fiber fusion spliced to the first end of said graded index multi-mode fiber. A reflective mirror coating is applied to a planar facet on the second end of said graded index multi-mode fiber. A plurality of mechanical attachments are spaced along the graded index multi-mode fiber and single-mode optical fiber that mechanically deform said graded index multi-mode fiber, when any one of said plurality of mechanical attachments is displaced relative to any other one of said plurality of mechanical attachments.

Abstract: Described are various configurations of integrated wavelength lockers including asymmetric Mach-Zehnder interferometers (AMZIs) and associated detectors. Various embodiments provide improved wavelength-locking accuracy by using an active tuning element in the AMZI to achieve an operational position with high locking sensitivity, a coherent receiver to reduce the frequency-dependence of the locking sensitivity, and/or a temperature sensor and/or strain gauge to computationally correct for the effect of temperature or strain changes.

Abstract: A sensor can include a plurality of imaging components configured to perform (1) subsurface imaging by acoustical excitation and optical detection, and (2) interferometric surface topographic measurement.

Abstract: A multi-axis force sensor is compact in that it comprises a single strand of optical fiber and a single, movable reflecting element having a reflecting surface separated from a fiber end-face by a gap, and yet is capable of measuring axially and/or laterally applied forces with high sensitivity. The force to be measured causes the reflecting surface to tilt, translate or deform. The single strand of fiber is configured to have multiple cores that carry multiple optical interrogation signals through an end-face of the fiber to incidence on the reflecting surface. The cores are configured so that the propagation vectors of the interrogation signals, as the signals emanate from the fiber end-face, make non-perpendicular angles with that end-face. Furthermore, the cores are configured to capture a portion of the interrogation signals back-reflected from the reflecting surface.

Abstract: A plasma processing apparatus for processing semiconductor substrates comprises a plasma processing chamber in which a semiconductor substrate is processed. A process gas source is in fluid communication with the plasma processing chamber and is adapted to supply a process gas into the plasma processing chamber. A RF energy source is adapted to energize the process gas into a plasma state in the plasma processing chamber. Process gas and byproducts of the plasma processing are exhausted from the plasma processing chamber through a vacuum port. At least one component of the plasma processing apparatus comprises a laterally extending optical fiber beneath a plasma exposed surface of the component wherein spatial temperature measurements of the surface are desired to be taken, and a temperature monitoring arrangement coupled to the optical fiber so as to monitor temperatures at different locations along the optical fiber.

Abstract: A motion-compensated injector system includes a handheld tool having a hollow shaft with a distal end for insertion into tissue of a subject. The system also includes an optical coherence tomography-based optical detection system having an optical fiber with a distal end at a fixed distance from the distal end of the hollow shaft, and an optical sensor to receive a signal from the optical fiber. The system further includes an actuator to move the hollow shaft in an axial direction, and a control unit to control the actuator. The optical detection system can monitor a distance between the distal end of the optical fiber and a reference portion of the tissue of the subject, and the control unit can control the actuator to move the hollow shaft to compensate for relative motion between the handheld tool and the portion of the tissue.

Abstract: An acoustic wave acquiring apparatus is used that includes: an array light source including a plurality of elements emitting measurement light; a controller controlling the wavelength of the measurement light, for each of or the plurality of elements; a Fabry-Perot interferometer including a first mirror upon which the measurement light is incident and a second mirror upon which an acoustic wave from a subject is incident; an optical sensor measuring a light quantity of reflected light by the first and the second mirror; and a processor acquiring an intensity of the acoustic wave on the basis of a change of the light quantity of the reflected light, which is a distance between the first mirror and the second mirror, occurring due to the incidence of the acoustic wave.

Abstract: A compact, low cost FTIR spectrometer with no moving parts includes an interferometer having optical paths through silicon waveguides. The optical path lengths are varied by changing the temperature and/or carrier density of at least one of the waveguides. In embodiments, the interferometer is a Mach-Zehnder interferometer. Embodiments vary both optical path lengths in opposite directions. In embodiments, a germanium or InGaAs IR detector is grown on the same wafer as the waveguides. Embodiments include a laser pump, such as a COT CW diode laser, and wavelength mixer, such as an OPGaAs or OPGaP converter, for up and/or down converting measured IR wavelengths into a range compatible with the waveguide and detector materials. The wavelength mixer can be a waveguide. Embodiments include a sample compartment and an IR source such as a glowbar. In embodiments, the sample compartment can be exposed to ambient atmosphere for analysis of gases contained therein.

Abstract: Disclosed herein are optical integration technologies, designs, systems and methods directed toward Optical Coherence Tomography (OCT) and other interferometric optical sensor, ranging, and imaging systems wherein such systems, methods and structures employ tunable optical sources, coherent detection and other structures on a single or multichip monolithic integration. In contrast to contemporary, prior-art OCT systems and structures that employ simple, miniature optical bench technology using small optical components positioned on a substrate, systems and methods according to the present disclosure employ one or more photonic integrated circuits (PICs), use swept-source techniques, and employ a widely tunable optical source(s).

Abstract: A control computation unit causes an optical modulator to change a polarization state to shift a phase of polarized light with which an object is irradiated, computes a spatial gradient of tomographic distribution of phase difference of an interference signal on the basis of phase differences of interference signals each obtained by each phase shift of the polarized light, and visually displays tomographic distribution of spatial gradient in association with tomographic distribution of stress on the display device. The control computation unit computes deformation rate vector distribution at cross-sectional positions of the object on the basis of optical interference signals, and further computes tomographic distribution of strain rate tensor.

Abstract: Some embodiments are directed to a multiplexed fiber sensor for a fiber optic hydrophone array, including a signal receiver configured to receive a signal from the fiber optic hydrophone sensor array and an interferometer. The interferometer is configured to produce a first signal component and a second signal component from the signal received from the hydrophone array, and also provided with a first polarization controller configured to control the polarization of the first signal component and a second polarization controller configured to control the polarization of the second signal component. A modulated carrier signal generator configured to generate a modulated carrier signal component based on the first signal component is also provided. A detector configured to output a demodulated output signal from the modulated signal component and the second signal component is included, wherein the modulated signal component and the second signal component output separately from the interferometer.

Abstract: A technique for measuring an optical coherent receiver is disclosed, where the optical coherent receiver recovers a data by an interference between signal light and local light. The technique includes steps of (i) equalizing optical lengths of the signal light and the local light from the optical source, respectively, and (ii) during a scan of the frequency, maximizing an output of the optical coherent receiver by the feedback control from an output of the optical coherent receive to the phase of the local light. The technique has a feature that, when the feedback control set a delay/lead in the phase of the local light to be 2V???, the delay/lead of the phase of the local light is decreased/increased by 2V?, where 2V? corresponds to one period of the wavelength of the local light.

Abstract: An optical module includes a board; a photoelectric transducer disposed on the board; an optical waveguide that is connected to the board and transmits light entering or emitted from the photoelectric transducer; an optical connector including a first end connected to the optical waveguide and a second end to be connected to an optical cable; a housing that houses the board, the photoelectric transducer, the optical waveguide, and the optical connector; and a conductive part that is provided between the optical waveguide and the housing, in contact with the housing, and formed of an elastic conductive material or a radio absorbing material.

Abstract: Various technologies for performing continuous-variable (CV) and discrete-variable (DV) quantum key distribution (QKD) with integrated electro-optical circuits are described herein. An integrated DV-QKD system uses Mach-Zehnder modulators to modulate a polarization of photons at a transmitter and select a photon polarization measurement basis at a receiver. An integrated CV-QKD system uses wavelength division multiplexing to send and receive amplitude-modulated and phase-modulated optical signals with a local oscillator signal while maintaining phase coherence between the modulated signals and the local oscillator signal.

Abstract: Multiplexed microvolt sensor systems and methods are described. An example system may include a pulsed light source, a first optical waveguide segment operatively coupled to the pulsed light source, an optical circulator including a first port, a second port, and a third port, the first port being operatively coupled to the first optical waveguide segment, a second optical waveguide segment operatively coupled to the second port of the optical circulator, and an array of sensor elements. Each of the sensor elements may include a detector and an electro-optical modulator, the electro-optical modulator being operatively coupled to the second optical waveguide segment.

Abstract: A digital-electrical to digital-optical converter converts the digital electric signal to a plurality of digital-optical signals. The plurality of digital signals are used in controlling one or more cross phase modulator semiconductor optical amplifiers (XMP-SOAs) in order to modulate a continuous wave optical signal and produce an analog-optical signal corresponding to the digital-electrical signals.

Abstract: There is provided a solid seismic streamer cable for use in seismic surveying in marine environments. The streamer is characterized by a buffer layer 2 which is provided with a cut-out 50 and a sensor element arranged in the cut-out 50. There is also provided an associated hydrophone for integration into the seismic streamer cable. The hydrophone is characteristic in a split-element sensor base 10, 11 being suited for efficient mounting into the cut-outs 50 of the seismic cable. There is also provided an associated accelerometer for integration into the seismic streamer cable. The accelerometer is characteristic by a split-element sensor base 30, 35 for being efficiently arranged into the cut-outs 50 of the seismic cable. A method of producing a seismic streamer cable according to the invention incorporating a hydrophone or accelerometer according to the invention is also provided.

Abstract: Provided is a compact, low-cost optical measuring apparatus capable of acquiring an image of a target to be measured without moving a mirror or using a wavelength-scanning light source or beam splitter. A laser beam emitted from a light source is split into first and second beams, and the first beam is focused as a signal beam onto the target by a lens for irradiation purposes, while the second beam is reflected as a reference beam by a mirror without irradiating the target. Then, a signal beam reflected by or scattered by the target is multiplexed with the reference beam and then enters interference optics, whereby three or more interference beams with different phases are generated and detected by photodetectors. Then, the detection signals are operated by a signal processing unit. During the measurement, the focus position of the first beam is moved at least in the optical axis direction.

Abstract: There is described a distributed optical fiber sensor for detecting one or more physical parameters indicative of an environmental influence on a sensor optical fiber, as a function of position along the sensor fiber. The sensor uses probe light pulses of different wavelengths. At least some of the probe light pulses may also be of different pulse lengths. The relative phase bias between interferometric signals in backscattered probe light of different wavelength pulses may also be controlled.

Abstract: An apparatus for determining optical fiber array polarity is disclosed. The apparatus may be used to determine optical signal loss or intensity. An adapter may be used to couple the apparatus to a variety of optical fiber connectors. The apparatus includes a position sensing detector and processing circuitry. The position sensing detector includes a sensor that receives optical signals and electrodes that output respective output signals in response to receipt of an optical signal. The processing circuitry receives the output signals and identifies locations at which the optical signals were incident on the sensor. The processing circuitry also determines the receiving position in the optical array of an optical fiber and a polarity of the optical array based on the receiving position and a corresponding transmitting position. The processing circuitry may determine an intensity or loss of the optical signal based on an aggregate of the output signals.

Abstract: A fiber-optic sensor can have a Michelson sensor portion and a Mach-Zehnder sensor portion. A first splitter-coupler can be configured to split incoming light between a first fiber portion and a second fiber portion. A first polarization-phase conjugation device can be configured to conjugate a polarization phase of incident light corresponding to the first fiber portion, and a second polarization-phase conjugation device can be configured to conjugate a polarization phase of incident light corresponding to the second fiber portion. Each of the first and second polarization-phase conjugation devices can be configured to reflect light toward a detector and through the respective first and second fiber portions. A coupler can be configured to join light in the first fiber portion with light in the second fiber portion, and a third fiber portion can be configured to receive light from the coupler and to illuminate a second detector.

Abstract: An illuminated surgical retractor system includes a surgical retractor and at least one illumination device. The surgical retractor includes an outer ring, a light-transmissive hollow inner ring, and a tubular retraction membrane which extends between the output ring and the inner ring and which has a first open end connected to and spread open by the outer ring and a second open end connected to and spread open by the inner ring. The illumination device is disposed in the inner ring and is operable to emit a light beam. The illumination device includes a magnetic component which is responsive to an applied magnetic field to cause the illumination device to change a direction in which the light beam is emitted.

Abstract: A temperature measurement apparatus includes a light source; a first splitter that splits a light beam into a measurement beam and a reference beam; a reference beam reflector that reflects the reference beam; an optical path length adjustor; a second splitter that splits the reflected reference beam into a first reflected reference beam and a second reflected reference beam; a first photodetector that measures an interference between the first reflected reference beam and a reflected measurement beam obtained by the measurement beam reflected from a target object; a second photodetector that measures an intensity of the second reflected reference beam; and a temperature calculation unit. The temperature calculation unit calculates a location of the interference by subtracting an output signal of the second photodetector from an output signal of the first photodetector, and calculates a temperature of the target object from the calculated location of the interference.

Abstract: Apparatus for spatially resolved temperature measurement, comprising at least one optical fiber (4) for spatially resolved temperature measurement, at least one laser light source (1), the light (11) from which can be coupled into the optical fiber (4), wherein those components (12, 12a, 12b) of the light (11) produced by the laser light source (1) which are scattered back in the optical fiber (4) can be coupled out of the optical fiber (4) and detected, modulator means (2) permitting the modulation of the light (11) that is to be coupled into the optical fiber (4), and also demodulator means (5, 6) which permit a demodulation of those components (12, 12a, 12b) of the light (11) which are coupled out of the optical fiber (4), wherein the demodulator means (5, 6) are designed as optical demodulator means (5, 6) and/or wherein the modulator means (2) are designed as optical modulator means (2).

Abstract: Described are a method and apparatus for high-speed phase shifting of an optical beam. A transparent plate having regions of different optical thickness is illuminated by an optical beam along a path of incidence that extends through the regions. The transparent plate can be moved or the optical beam can be steered to generate the path of incidence. The optical beam exiting the transparent plate has an instantaneous phase value according to the region in which the optical beam is incident. Advantageously, the phase values are repeatable and stable regardless of the location of incidence of the optical beam within the respective regions, and phase changes at high modulation rates are possible. The method and apparatus can be used to modulate a phase difference of a pair of coherent optical beams such as in an interferometric fringe projection system.

Abstract: Described are a method and apparatus for high-speed phase shifting of an optical beam. A transparent plate having regions of different optical thickness is illuminated by an optical beam along a path of incidence that extends through the regions. The transparent plate can be moved or the optical beam can be steered to generate the path of incidence. The optical beam exiting the transparent plate has an instantaneous phase value according to the region in which the optical beam is incident. Advantageously, the phase values are repeatable and stable regardless of the location of incidence of the optical beam within the respective regions, and phase changes at high modulation rates are possible. The method and apparatus can be used to modulate a phase difference of a pair of coherent optical beams such as in an interferometric fringe projection system.

Abstract: A distance measuring apparatus and method that enable high-precision and high-speed measurement by canceling variations of a delay circuit in the apparatus are provided. Pulsed light is branched into first and second reference light, and transmitted measurement light, and the difference in detection time among the first reference light along a first path with no optical variations, the second reference light along a second path with an optical delay, and received measurement light from an object to be measured is measured. The received measurement light and the first reference light are temporally separate, distance is calculated from the difference in detection time between the received measurement light and the first reference light.

Abstract: Low-cost interface property measuring device and method enabling high-precision and simple measurement of an interface property.

Abstract: A tunable optical filter apparatus and method are disclosed. The apparatus may include a filter driver, a filter device, a detector device and a controller device. The filter driver generates a filter driver signal, including a dither signal. The controller device may be coupled to the detector device, the filter device and the filter driver. The controller device may receive the detector output signal and determine a ratio of the odd order harmonic signal to the even order harmonic signal with respect to the dither frequency. The controller device may also compare the ratio to a predetermined setpoint ratio and generate a control feedback signal for generating a new filter driver signal. The control feedback signal may be based on the comparison of the ratio of the odd order harmonic signal to the even order harmonic signal, to the predetermined setpoint ratio that corresponds to a desired filter operating frequency.