Abstract: The disclosed technology can be implemented in photonics integrated circuit (PIC) to provide an optical frequency detection device for measuring an optical frequency of light using two Mach-Zehnder interferometer where the delay imbalance in the first interferometer is configured to be one quarter wavelength longer than that of the second interferometer to produce an additional phase difference between the two arms. The two outputs of each interferometer are then detected by two photodetectors to produce two complementary interference signals. The difference between the two complementary interference signals of the first interferometer is a sine function of the optical frequency while the difference between the two complementary interference signals of the second interferometer is proportional to a cosine function of the optical frequency. Using the sine/cosine interpretation algorithm commonly used for the rotation encoders/decoders, any increments in optical frequency can be readily obtained.

Abstract: A Mach-Zehnder interferometer (MZI) filter comprising one or more passive compensation structures are described. The passive compensation structures yield MZI filters that are intrinsically tolerant to perturbations in waveguide dimensions and/or other ambient conditions. The use of n+1 waveguide widths can mitigate n different sources of perturbation to the filter. The use of at least three different waveguide widths for each Mach-Zehnder waveguide can alleviate sensitivity of filter performance to random width or temperature variations. A tolerance compensation portion is positioned between a first coupler section and a second coupler section, wherein the tolerance compensation portion includes a first compensation section having a second width, a second compensation section having a third width and a third compensation section having a fourth width, wherein the fourth width is greater than the third width and the third width is greater than the second width.

Abstract: A three-dimensional profiler includes a broadband radiation source. An interferometric system receives the radiation and includes first and second beam splitters, a moving time delay-inducing reflector, and a stationary reflector. The interferometric system creates a time-delayed optical sample radiation source and an optical reference incident radiation source with the first beam splitter. A stationary sample holder receives the optical sample incident radiation. A reference plane receives the optical reference incident radiation. A detector receives an interference signal from reflected or scattered optical sample radiation and reflected or scattered optical reference radiation. A processor extracts an optical path difference between the reference plane and the sample and reconstructs a three-dimensional morphology of the sample.

Abstract: A phase measurement method is presented which causes wavelength-multiplexed pulsed light to be incident on a measurement target optical fiber, produces a scattered light vector obtained by plotting scattered light from the measurement target optical fiber for each wavelength onto a two-dimensional plane having the in-phase component thereof on the horizontal axis and the orthogonal component thereof on the vertical axis, rotates the produced scattered light vector for each wavelength at each place in the measurement target optical fiber to align the directions of the vectors, generates a new vector by calculating the arithmetic average of the vectors having the aligned directions, and calculates the phase by using the values of the in-phase and orthogonal components of the generated new vector.

Abstract: Disclosed herein are medical systems and devices that include an elongate probe configured for insertion into a patient, where a multi-core optical fiber extends along the elongate probe. The optical fiber includes sensing core fibers that extend distally along a flexible distal tip section having a bending flexibility that exceeds a flexibility of a main probe section. The optical fiber may further include illumining core fibers, imaging core fibers, and an electrical conductor. An electrode at the distal end provides for detection of an ECG signal. The distal tip section may also be steerable. The system includes a console having processors and logic stored in memory. The logic facilitates portraying of a shape of the elongate probe, an ECG waveform and/or an image of an interior of the patient. The elongate probe further includes a shape memory material defining a transition temperature.

Abstract: There is provided a method, apparatus and system for calibrating and operating an optical wavemeter. In calibration, training optical signals with known wavelengths are input to a wavemeter, and corresponding photodetector measurements are obtained. Optical parameters of the wavemeter are then estimated based on the measurements. The optical parameters are indicative of a length difference ?L between two unequal-length waveguides in an optical delay line of the wavemeter; and scattering parameters of a multi-mode interferometer (MMI) coupler of the wavemeter. The estimation process involves a (e.g. golden-section) search to determine one or more output values for at least one of the optical parameters, based on an objective function which indicates a difference expected and actual measurements. The expected measurements are generated based on a numerical model incorporating candidate values for the optical parameters.

Abstract: Consistent with some disclosed embodiments, an optical switch includes: a scheduler; and a buffer for buffering an optical packet including, arranged in a circuit, a clock generator for generating a clock signal, an optical unbalanced Mach Zehnder Interferometer (MZI) and a fiber delay line (FDL) having an FDL length, wherein the optical packet has an optical packet signal, wherein the scheduler is configured to insert the optical packet into the buffer and to determine a number of circulations of the optical packet through the circuit, wherein the MZI modulates the clock signal based on the optical packet signal to create a reshaped optical packet after each circulation of the optical packet through the circuit, and wherein the FDL introduces a delay in the optical packet proportional to the FDL length.

Abstract: A shock wave detection system includes an optical sensor configured to generate a sensor signal based on the received laser light, a processor, and a memory. The memory includes instructions stored thereon, which when executed by the processor cause the system to: generate a sensor signal based on the laser light; perform a digital fast Fourier transform on the sensor signal; determine a power spectral density of the sensor signal based on the digital fast Fourier transform; determine a difference in a frequency content before, during, and after a shock wave transition event based on the power spectral density; and determine a passing of the shock wave based on the difference in the frequency content.

Abstract: The invention refers to a frequency shifter for heterodyne interferometry measurements, comprising a chip, an input waveguide configured to guide a light beam, at least four phase modulators, each being arranged to receive the light beam from the input waveguide and configured to modulate a phase of the light beam, an output combiner being arranged to let the light beams modulated by each phase modulator interfere, a first output waveguide coupled to the output combiner and configured to receive the modulated light beams constructively interfering at the output combiner, a second output waveguide coupled to the output combiner and configured to receive the modulated light beams destructively interfering at the output combiner, wherein the input waveguide, the phase modulators, the output combiner, the first output waveguide and the second output waveguide are arranged on the chip.

Abstract: A magneto-optic current transformer for measuring a current intensity of an electric current in an electrical conductor includes two light-guide units, each with an input polarizer, an output polarizer and a light guide arranged between the input and the output polarizer. A light-supply device is included which is configured to supply light to the light-guide units on the input side, and an analysis device which is configured to measure a luminous intensity of light output by the light-guide unit at the output side for each light-guide unit and to ascertain the current intensity of the electric current through the electrical conductor from the measured luminous intensities. A polarization axis of the output polarizer of each light-guide unit is rotated through a polarization angle in relation to a polarization axis of the input polarizer of the light-guide unit and the polarization angles of the two light-guide units differ from one another.

Abstract: A broadband interferometry for a measurement range extension beyond a coherence length of a light source is achieved through a local oscillation of the reference beam is replicated by a cavity multiplication or cascading optical delayed lines with a fiber optic cavity, and quantifiable optical properties including a wavelength group delay, a chromatic dispersion, a polarization mode dispersion and a model dispersion are inserted into the local oscillation of the reference beam to incrementally quantify the replicated copies of the local oscillation as the number of the delayed copies of the local oscillation increase for extension of a measurement rage to the target.

Abstract: A checkerboard imager comprises an aperture pair array in a rectangular shape, a 2D optical waveguide grating array, a 3D optical waveguide beam transmission array, a 2D optical waveguide quadrature modulation coupler array, and a photoelectric conversion data acquisition and image processing module. An object light is converged by sub-apertures of the aperture pair array, collected by the 2D optical waveguide grating array, and split into narrow-spectrum beams which are output to the 3D optical waveguide beam transmission array for cross-pairing, modulated and coupled by the 2D optical waveguide quadrature modulation coupler array, and reach the photoelectric conversion data acquisition and image processing module to obtain an object image. A method for implementing the checkerboard imager is provided where each module is independently manufactured and then integrated to improve yield of the modules and imager's optical efficiency, expand equivalent apertures, and improve working capability.

Abstract: An apparatus and method of inspection are provided that inspects the end-face of two or more fiber optic connectors simultaneously without the need to move a probe from one end-face to another end-face and inspecting them one by one.

Abstract: The present disclosure is to provide a measurement chip, a measuring device, and a measuring method which can accurately estimate an analyte concentration with a simple configuration. A measurement chip may include a propagation layer, an introductory part, a drawn-out part and a reaction part. Through the propagation layer, light may propagate. The introductory part may introduce the light into the propagation layer. The drawn-out part may draw the light from the propagation layer. The reaction part may have, in a surface of the propagation layer where a reactant that reacts to a substance to be detected is formed, an area where a content of the reactant changes monotonously in a perpendicular direction perpendicular to a propagating direction of the light, over a given length in the propagating direction.

Abstract: An isolator includes a first waveguide with a linear shape and a second waveguide with an annular shape on a substrate including a substrate surface, the first waveguide being positioned along the substrate surface. The first waveguide and the second waveguide each include a core and a cladding. The first waveguide includes a first end, a second end, and a port at each of the first end and the second end for input and output of electromagnetic waves. The core of the second waveguide includes a non-reciprocal member in at least a portion of a cross-section intersecting a direction in which the second waveguide extends.

Abstract: A wavelength monitoring apparatus includes a wavelength monitoring circuit. The wavelength monitoring circuit includes: a split circuit that splits an input optical signal into two; an optical delay circuit that applies a delay time difference to the two split optical signals; and a two-input two-output optical multiplexer/demultiplexer circuit that outputs a result of applying multiplexing interference to the optical signals to which the delay time difference has been applied. The wavelength monitoring apparatus further includes photoelectric conversion elements that perform photoelectric conversions on the two optical signals output from the wavelength monitoring circuit so as to output electrical signals.

Abstract: A system includes a radiation source configured to emit a radiation beam. The system further includes a first optical sensor configured to detect a first intensity of a first portion of the radiation beam reflected from a surface of an object. The system further includes a second optical sensor configured to detect a second intensity of a second portion of the radiation beam scattered by the surface of the object. The system further includes a processing device communicatively coupled to the first optical sensor and the second optical sensor. The processing device is configured to determine at least one of a roughness or an emissivity of the surface of the object based on a comparison of the first intensity and the second intensity.

Abstract: An optical component for an attenuated total reflection multispectral imaging device, which includes a support substrate and at least two planar waveguides, and wherein the planar waveguides and the support substrate are superimposed together, with the support substrate which covers the planar waveguides; each of the planar waveguides includes at least one diffraction grating; and at least two of the planar waveguides have their diffraction gratings which have values of the average pattern distribution pitch which are distinct from each other; the support substrate includes, on one side opposite the planar waveguides, a face forming an exchange interface with a sample; and an exit face of the optical component corresponds to a lateral face of the support substrate.

Abstract: A method is provided of forming a stain assessment target for a biological material staining system. At least one region of a substrate is provided upon a support such as a microscope slide. The substrate is formed from an optically transmissive material which is an analogue of biological tissue. A biological tissue sample for inspection is also provided upon the support. The support, including the at least one region, together with the biological tissue sample and then stained by applying at least one biological tissue stain under similar staining conditions.

Abstract: An integrated anchoring structure of basalt fiber reinforced plastic (BFRP) bars for a reservoir bank slope includes: a plurality of BFRP anchoring bars, where each of the BFRP anchoring bars includes a plurality of BFRP bars bonded to one another, a lower steel casing pipe, an upper steel casing pipe and a steel strand bonded to an upper portion of the upper steel casing pipe and aligned with the BFRP bars, and a grating array temperature sensing optical cable, a grating array stress sensing optical cable and a grating array vibration sensing optical cable are bonded in each of the BFRP bars; a plurality of shear-resistant bricks distributed on structural planes; a pouring base arranged at a bottom of the anchoring borehole; and an anchoring section arranged at an upper portion of the pouring base.

Abstract: The present disclosure relates to integration of integrated photonics-based optical gyroscopes and fiber-based optical gyroscopes into portable apparatuses that may include compass features. Novel small-footprint modularized fully integrated photonics optical gyroscopes are used for non-critical axes. However, for at least one critical axis, a fiber-optic gyroscope can be used to provide bias stability below 0.1°/Hr, which is directly correlated to predicting positional accuracy in the centimeter range. The positional accuracy results from the compassing ability of the gyroscope (referred to as gyrocompass) to calculate direction of heading using the earth's rotation.

Abstract: The disclosed embodiments provide a system that non-invasively analyzes blood flow in a sample of living tissue. During operation, the system obtains light from a temporally coherent source, and splits the obtained light between a reference path and a sample path. Next, the system multiply scatters light from the sample path by passing the light through the sample. The system then recombines light from the reference path and the multiply scattered light from the sample path. Next, the system uses a sensor array to detect an interference pattern resulting from the recombination. Finally, the system analyzes signals from the sensor array to determine a blood flow in the sample.

Abstract: A wavelength monitoring circuit obtains a light output proportional to only an input optical signal, independent of wavelength, by adding a light split circuit to the configuration in the related art, or changing the light split circuit to a light trifurcation circuit. In addition, wavelength monitoring with high accuracy is possible while improving the resistance to noise. The extraction of the light output proportional to only the input optical signal is performed by a light split circuit for input light at the top stage of the wavelength monitoring circuit or a light split circuit for interference in a stage in the middle of the circuit. The changed light split circuit causes the MZI included in the wavelength monitoring circuit to operate in a state of losing the balance of the configuration or the optical signal level, and increases the signal level near the bottom portion of the transmission characteristics.

Abstract: Photonic devices are disclosed including a first cladding layer, a first electrical contact comprising a first lead coupled to a first dielectric portion, a second electrical contact comprising a second lead coupled to a second dielectric portion, a waveguide structure comprising a slab layer comprising a first material, and a second cladding layer. The slab layer may be coupled to the first dielectric portion of the first electrical contact and the second dielectric portion of the second electrical contact. The first dielectric portion and the second dielectric portion may have a dielectric constant greater than a dielectric constant of the first material.

Abstract: Example embodiments include an optical interrogation system with a sensing fiber having a single core, the single core having multiple light propagating modes. Interferometric apparatus probes the single core multimode sensing fiber over a range of predetermined wavelengths and detects measurement interferometric data associated with the multiple light propagating modes of the single core for each predetermined wavelength in the range. Data processing circuitry processes the measurement interferometric data associated with the multiple light propagating modes of the single core to determine one or more shape-sensing parameters of the sensing fiber from which the shape of the fiber in three dimensions can be determined.

Abstract: Consistent with some disclosed embodiments, an optical switch includes: a scheduler; and a buffer for buffering an optical packet including, arranged in a circuit, a clock generator for generating a clock signal, an optical unbalanced Mach Zehnder Interferometer (MZI) and a fiber delay line (FDL) having an FDL length, wherein the optical packet has an optical packet signal, wherein the scheduler is configured to insert the optical packet into the buffer and to determine a number of circulations of the optical packet through the circuit, wherein the MZI modulates the clock signal based on the optical packet signal to create a reshaped optical packet after each circulation of the optical packet through the circuit, and wherein the FDL introduces a delay in the optical packet proportional to the FDL length.

Abstract: The technology of this application relates to a data read/write apparatus and an electronic device, which relate to the data storage field, and can improve data read/write performance. The data read/write apparatus includes a first laser, configured to output a first optical pulse based on a control signal, where the control signal is a signal obtained based on to-be-written data, a dispersion compensator, configured to perform dispersion compensation on the first optical pulse to output a second optical pulse, and an optical fiber lens, connected to the dispersion compensator by using an optical fiber, and configured to focus the second optical pulse onto an optical storage medium, to write the to-be-written data to the optical storage medium.

Abstract: A temperature measurement technology includes generating an input optical signal at a wavelength using an optical signal generator, splitting the input optical signal into a first beam and a second beam, optically transmitting the first beam through the first arm of an interferometer, transmitting the second beam through a second arm of the interferometer that introduces a phase shift in the second beam relative to the first beam, combining at least a portion of the transmitted first beam and the transmitted phase-shifted second beam to produce an output optical signal, measuring an optical signal intensity of the output optical signal, and correlating the measured optical signal intensity with a temperature to produce a measured temperature. Alternatively, the input optical signal may be transmitted through two or more interferometers.

Abstract: Disclosed herein is a system, apparatus and method directed to placing a medical device into a body of a patient, each performing or including operations of providing a broadband incident light signal to a plurality of core fibers of a multi-core optical fiber, receiving reflected light signals of different spectral width, processing the reflected light signals associated with the plurality of core fibers to determine (i) a physical state of the multi-core optical fiber relating to the medical device including the multi-core optical fiber, and (ii) an orientation of the multi-core optical fiber relative to a reference frame of the body. Additional operations include generating a display illustrating the physical state of the multi-core optical fiber based at least on the orientation determined during processing of the reflected light. Typically, the display is a two-dimensional representation of the multi-core optical fiber in accordance with the determined orientation.

Abstract: The present invention relates to an intelligent fiber optical distributed acoustic sensing (FODAS) system and method based on an artificial intelligence (AI) chip, belonging to the field of distributed optical fiber sensing technologies. The system comprises a light source, a modulator, an optical amplifier, a sensing part, a data processor, a photoelectric detector, and an alarm unit, where the data processor is specifically an AI chip; the light source, the modulator, the optical amplifier and port a of a circulator are connected in sequence, port b of the circulator is connected to an optical fiber, port c of the circulator is connected to the photoelectric detector, an output end of a detector is connected to the data processor, an output end of the data processor is connected to the alarm unit; and the data processor receives external acoustic signals and extracts amplitude and frequency features of the external acoustic signals to identify the type.

Abstract: Apparatuses comprising cascaded or series configurations of Mach-Zehnder electrooptic modulators, where the nonlinearities of the cascaded and series configurations of Mach-Zehnder electrooptic modulators increase signal bandwidth and boost signal fidelity in electronic digital to analog converters. The Mach-Zehnder electrooptic modulators are combined with photodiode detectors that are used to convert signals from the optical domain to the electrical domain.

Abstract: A method for manufacturing an optical modulator is disclosed. The method includes a step of preparing a Mach-Zehnder modulator, a step of acquiring, based on a light transmittance in an arm waveguide, a relationship between a voltage applied to an electrode and a phase change amount of light propagating through the arm waveguide, a step of acquiring, based on the relationship, a voltage in which the phase change amount of the light propagating through the arm waveguide has a predetermined when the light is modulated, and a step of storing the voltage in a storage unit.

Abstract: A wearable device includes a device housing configured to be worn on a first surface of a user, a set of one or more SMI sensors, and a processor. The set of one or more SMI sensors is mounted within the device housing and configured to emit a set of one or more beams of electromagnetic radiation, with each beam emitted in a different direction extending away from the first surface. The set of one or more SMI sensors is also configured to generate a set of one or more SMI signals containing information about a relationship between the device housing and a second surface. The processor is configured to extract the relationship between the device housing and the second surface from digitized samples of the set of one or more SMI signals.

Abstract: A device may determine a time-of-flight measurement by performing a sample of a sensor based on light received via at least one first spectral filter, wherein the at least one first spectral filter is associated with a spectral range for a time-of-flight measurement; determine that a condition is satisfied with regard to the time-of-flight measurement, wherein the condition relates to an orientation or a position of the sensor or the sensor device relative to a measurement target; trigger a spectrometry measurement to be performed based on determining that the condition is satisfied with regard to the time-of-flight measurement; and perform, based on light received via at least one second spectral filter and by performing a sample of the sensor, the spectrometry measurement for the measurement target based on the condition being satisfied with regard to the time-of-flight measurement.

Abstract: A particle detection method detects presence and location of particles on a target using measured signals from a plurality of structured illumination patterns. The particle detection method uses measured signals obtained by illuminating the target with structured illumination patterns to detect particles. Specifically, the degree of variation in these measured signals in raw images is calculated to determine whether a particle is present on the target at a particular area of interest.

Abstract: The present invention relates to a device (10) for determining an arterial compliance of a subject (12). The device (10) comprises an inflatable cuff (14), a pressure sensor (18) which is configured to sense a pressure signal (52) that is indicative of a pressure within the cuff (14), a second sensor (20) which is at least partly integrated in the cuff (14) and configured to sense a second signal (56) that is responsive to expansions and contractions of the cuff (14) caused by a pulsating blood flow in an artery (50) of the subject (12), and a processing unit (22). The processing unit is configured to determine based on said part of the pressure signal (52) a pulse pressure of the subject (12), to determine based on said part of the second signal (56) an arterial volume change of the artery (50) of the subject (12) during at least one cardiac cycle, and to determine the arterial compliance of the subject (12) based on pulse pressure and the arterial volume change.

Abstract: A compact spectrometer is disclosed that is suitable for use in mobile devices such as cellular telephones. In preferred embodiments, the spectrometer comprises a filter, at least one Fourier transform focusing element, a micro-lens array, and a detector, but does not use any dispersive elements. Methods for using the spectrometer as an end-user device for performing on-site determinations of food quality, in particular, by comparison with an updatable database accessible by all users of the device, are also disclosed.

Abstract: A sensor apparatus, such as a pressure gauge, comprises a sensor arranged to produce a sensor output signal that varies with a measured parameter such as pressure, and a plurality of output channels each arranged to receive the sensor output signal. The output channels are each optimized for a different range of the measured parameter. The apparatus further comprises an analog to digital converter (ADC) and control module arranged to select one of the output channels and connect it to the ADC so as to produce a digital channel output, and an output module configured to generate an output reading from the digital channel output of the selected channel.

Abstract: A device for monitoring and identifying a mountain torrent and debris flow and a method for early warning of disasters relate to the technical field of debris flow protection. The device includes a computation device, sensors, an amplifier and an analog-to-digital converter. The sensors convert an acquired impact force signal into a digital signal by the amplifier and the analog-to-digital converter, and transmits the digital signal to the computation device. The computation device utilizes the digital signal to compute an energy coefficient of a liquid impact signal and a solid-liquid impact energy ratio, and a debris flow mode is monitored and identified in combination with a threshold range of the energy coefficient and a threshold range of the solid-liquid impact energy ratio. The device identifies the nature of the mountain torrent and debris flow through time-frequency analysis of an impact force signal generated by the debris flow to sensors.

Abstract: A through-bore spool apparatus for use in deploying multiple spoolable media in a bore is disclosed. The through-bore spool apparatus comprises a first spool comprising a first spool axis and a first spoolable medium wound around the first spool axis, and a second spool comprising a second spool axis and a second spoolable medium wound around the second spool axis. The first and second spoolable media are de-spoolable simultaneously from the respective first and second spools during movement of the through-bore spool apparatus along a bore.

Abstract: A digital topographic model of the luminal surface is generated by projecting an optical pattern on the luminal surface from the first location within the lumen. At least a portion of the projected pattern is detected from a second location within the lumen which is based apart from the first location. The dimensions of the luminal wall can be measured by triangulation in order to produce the digital topographic model of the body lumen.

Abstract: Laser Side Mode Suppression Ratio (SMSR) control is provided via a logic controller configured to measure an SMSR of a carrier wave upstream of a modulator and measure an Average Optical Power (AOP) of the carrier wave downstream of the modulator; transmit a bias voltage based on the SMSR and the AOP to a laser driver for a laser generating the carrier wave; and transmit an attenuation level based on the SMSR and the AOP to a Variable Optical Attenuator (VOA) upstream of the modulator. In various embodiments the attenuation level and bias voltage can rise or fall together, or one may rise and one may fall to ensure the output optical signal meets specified SMSR and AOP values.

Abstract: There is described a method of making an acoustic sensor having a frequency response approximating a desired frequency response. The method comprises wrapping optical fiber around a core according to a wrapping pattern. The wrapping pattern is determined from an impulse response of the acoustic sensor. The impulse response is determined from the desired frequency response of the acoustic sensor.

Abstract: The present invention relates to an optical fiber BOCDA sensor. A purpose of the present invention is to provide an optical fiber BOCDA sensor which uses two phase codes to control a correlation peak position, thereby further simplifying control design and device configuration and improving spatial resolution to enhance a sensing performance and detection accuracy in comparison with the prior art.

Abstract: A method for all-optical reduction of inter-channel crosstalk for spectrally overlapped optical signals for maximizing utilization of an available spectrum includes receiving a plurality of spectrally overlapped optical signals modulated with data. The method further includes generating conjugate copies of each of the plurality of optical signals using non-linear optics. The method further includes selecting the conjugate copies and adjusting an amplitude, a phase, and a delay of the conjugate copies. The method further includes performing inter-channel interference (ICI) compensation on the spectrally overlapped optical signals in an optical domain by adding the adjusted conjugate copies to the spectrally overlapped optical signals.

Abstract: An apparatus for monitoring strain in an optical chip in silicon photonics platform. The apparatus includes a silicon photonics substrate shared with the optical chip. Additionally, the apparatus includes an optical input configured in the silicon photonics substrate to supply an input signal of a single wavelength. The apparatus further includes a first waveguide arm and a second waveguide arm embedded in the silicon photonics substrate to form an on-chip interferometer. The second waveguide arm forms a delay line being disposed at a region in or adjacent to the optical chip. The on-chip interferometer is configured to generate an interference pattern serving as an indicator of strain distributed at the region in or adjacent to the optical chip. The interference pattern is caused by a temperature-independent phase shift at the single wavelength of the interferometer between the first waveguide arm and the second waveguide arm.

Abstract: To provide patient status determination device, which receives continuous biological information from a state detection device that continuously detects biological information of a patient and measured biological information from a measuring device that measures biological information of the patient, appropriately determines the state of the patient, based on the received continuous biological information and the measured biological information, whereby it is possible to determine the state of the patient properly, based on the plurality of biological information of the patient.

Abstract: A method or apparatus for narrowing the linewidth of a single mode laser is provided. The linewidth of a single mode laser is narrowed by injecting an optical feedback simultaneously into the first laser cavity mirror and the second laser cavity mirror of the single mode laser.

Abstract: An optical sensing system for detecting fiber events along an optical cable under test (CUT) having forward and feedback fibers and multiple pairs of optical couplers interconnected along the forward and feedback fibers in a ladder topology. An optical transmitter generates an optical probing signal for a forward fiber, wherein the couplers along the forward fiber provide tapped portions of the probing signal to the couplers along a feedback fiber to form a combined optical feedback signal in the feedback fiber. A reference coupler is connected between the transmitter and the forward fiber to tap an optical reference signal from the probing signal, and a feedback coupler is connected to combine the reference signal and the feedback signal. An optical receiver receives and processes the combined reference and feedback signals from the feedback coupler to detect fiber events along the CUT.

Abstract: A measuring arrangement for fiber Bragg grating measurement points and particularly a measuring arrangement for two fiber Bragg gratings (FBG), wherein a first measurement point is subjected to tension and a second measurement point is subjected to pressure, or vice versa. The circuit arrangement includes a broadband light source, a first beam splitter, a second beam splitter, a third beam splitter, a fourth beam splitter, a fifth beam splitter, photodiodes and an optical delay element.