Abstract: An EM receiver instrument suitable for making underwater electric field measurements. The EM receiver comprises a dipole antenna; an AM modulator for applying modulation to a signal detected by the antenna; a fiber-optic voltage sensor and an application of AM demodulator for applying demodulation to the signal. The fiber-optic sensor may be an interferometric voltage sensor or a phase sensitive voltage sensor.

Abstract: Provided is an observation device and a method of observing capable of clearly obtaining information relating to a boundary part where a medium inside an observation object changes. An observation device (1) is a device for observing an observation object (2) including a sensitivity factor in which a dipole moment changes by sensing an electromagnetic wave (31). An output part (11) outputs the electromagnetic wave (31) and the dipole moment of the sensitivity factor included in the observation object (2) is changed by the electromagnetic wave (31). A detector part (12) detects, of the electromagnetic wave (31) outputted from the output part (11), a signal electromagnetic wave (33) which comes through the observation object (2) and a reference electromagnetic wave (32) which bypasses the observation object (2). A control part (13) analyzes the structure of the observation object (2) based on the detection results of the detection part (12).

Abstract: According to embodiments of the present invention, an optical sensing system is provided. The optical sensing system includes a resonator arrangement including a first resonator, wherein an effective refractive index of the first resonator is changeable in response to a change in a refractive index of a cladding of the first resonator, and a second resonator to which a current or voltage being adjustable in response to a change in the effective refractive index of the first resonator is applied, wherein the optical sensing system is configured to determine the change in the effective refractive index of the first resonator based on a change in the current or voltage applied to the second resonator. Further embodiments provide a method of determining a change in an effective refractive index of a resonator of an optical sensing system.

Abstract: An optical measuring probe for measuring inner and/or outer diameters of objects, uses a first optical element for focusing or collimating an optical beam onto a surface of an object. A second optical element for splitting the optical beam into a first measuring beam and a second measuring beam is provided in the optical measuring probe in such a way that the second measuring beam is guided out of the measuring probe in a direction opposite the direction of the first measuring beam and that the first measuring beam forms a first scan point and the second measuring beam forms a second scan point. Also described is a corresponding method for measuring diameters using the optical measuring probe. The optical measuring probe and the associated method make it possible to optically measure inner and outer diameters of measuring probes objects in a simple manner.

Abstract: Techniques and devices for measuring polarization crosstalk in birefringence optical media including polarization maintaining fiber.

Abstract: The invention relates to an optical device for interferometric analysis of the condition of the internal surface of a tube (11). The device comprises an optical fibre (3), the free end of which is pointed and then bevelled at the single core thereof and the bevelled surface is metalised (10), such that only part of the surface of the fibre core participates in reflecting the incident beam perpendicularly to the axis of the fibre.

Abstract: An optical device, a method of configuring an optical device, and a method of using a fiber Bragg grating is provided. The optical device includes a fiber Bragg grating, a narrowband optical source, and at least one optical detector. The fiber Bragg grating has a power transmission spectrum as a function of wavelength with one or more resonance peaks, each comprising a local maximum and two non-zero-slope regions with the local maximum therebetween. The light generated by the narrowband optical source has a wavelength at a non-zero-slope region of a resonance peak that is selected such that one or more of the following quantities, evaluated at the resonance peak, is at a maximum value: (a) the product of the group delay spectrum and the power transmission spectrum and (b) the product of the group delay spectrum and one minus the power reflection spectrum.

Abstract: There is provided a frequency tunable laser system comprising a laser, frequency varying means arranged for varying an optical frequency output of the laser, an intensity sensor arranged for receiving light from the laser, and a processor arranged for controlling the frequency varying means for varying the optical frequency output of the laser and receiving an intensity signal from the intensity sensor for monitoring the intensity output of the laser. The frequency tunable laser system further comprises an external reflective surface, in use, fixedly arranged in a light path of the laser beam outside the laser cavity at a predefined distance from the second reflective surface along the light path of the laser beam to reflect part of the emitted laser beam back into the laser cavity.

Abstract: A system that incorporates teachings of the present disclosure may include, for example, a method for aligning first and second light signals on an optical path directed to a target, where the first light signal provides a visualization of the target, and a portion of the second light signal reflects from at least one subsurface of the target. The method also includes aligning a first focal point of the first light signal and a second focal point of the second light signal, where the first focal point is at least in a first proximate location of the second focal point, and adjusting a first position of the first and second focal points to be in at least a second proximate location of the target without adjusting the at least first proximate location of the first focal point relative to the second focal point. Other embodiments are disclosed.

Abstract: The invention is an apparatus and method of eliminating polarization-induced fading in interferometric fiber-optic sensor system having a wavelength-swept laser optical signal. The interferometric return signal from the sensor arms are combined and provided to a multi-optical path detector assembly and ultimately to a data acquisition and processing unit by way of a switch that is time synchronized with the laser scan sweep cycle.

Abstract: Provided are an optical element and a wavelength monitor capable of detecting a wavelength with high accuracy and at high speed while suppressing a size. The optical element includes: a branch waveguide section configured to branch an input light beam and generate two outputs routed via paths having mutually different optical path lengths; and an optical synthesis section configured to synthesize the two outputs and output two optical signals having different light intensities with regards to a wavelength of the input light beam and exhibiting a mutual phase difference.

Abstract: An optical probe system has a light source fiber-delivered and the detector fiber-coupled for analyzing carrier fringes using a line sensor to measure displacement and tilt. Simultaneous surface metrology to measure both the front and back surface of the same optic, is enabled provided the two surfaces are substantially parallel to within the measurement range. Alternatively, the front surface can be measured and then subsequently the back surface.

Abstract: A fiber-optic interferometer comprising an optical fiber wound to form a fiber coil into which two partial light beams of a first light source can be coupled. The Bragg structure is integrated into the fiber coil. Said Bragg structure comprises an optical fiber having a periodically varying refractive index. In a method for determining physical state parameters in the interior of a fiber coil of a fiber optic interferometer information about physical state parameters in the interior of the fiber coil is obtained on the basis of the reflection wavelength of a Bragg structure comprising an optical fiber having a periodically varying refractive index is integrated into the fiber coil.

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: Embodiments include optofluidic apparatus that may be used to detect and manipulate nanoparticles or biomolecules within a fluid. To achieve that result, the embodiments use a fluidic channel located over a substrate. Particular embodiments also use: (1) an optical waveguide located over the substrate and particularly within the fluidic channel along with an optical resonator that may or may not be located within fluidic channel; and also (2) a phase shifter component coupled to either the waveguide or the optical resonator. Additional embodiments use an MZI or an MZI with an optical resonator to further provide the phase shifter component coupled to one arm of the MZI or the optical resonator.

Abstract: A device and method include a broadband light source in communication with a waveguide to provide a light signal for interrogating each of a plurality for sensors within the waveguide. An analyzer modulates the light signal with a microwave signal and demodulates and evaluates light signals reflected by the sensors. An amplitude and a phase of each reflected signal from each sensor is distinguished in the time domain and the modulated signal is reconstructed in the frequency domain.

Abstract: In part, aspects of the invention relate to methods, apparatus, and systems for intensity and/or pattern line noise reduction in a data collection system such as an optical coherence tomography system that uses an electromagnetic radiation source and interferometric principles. In one embodiment, the noise is intensity noise or line pattern noise and the source is a laser such as a swept laser. One or more attenuators responsive to one or more control signals can be used in conjunction with an analog or digital feedback network in one embodiment.

Abstract: The present invention relates to an optical sensing system (1) for determining the position and/or shape of an associated object (O), the system comprises an optical fibers (10) having one or more optical fiber cores (9) with one or more fiber Bragg gratings (FBG, 8) extending along the full length where the position and/or shape is be to determined of said object (O). A reflectometer (REFL, 12) measures strain at a number of sampling points along the optical fiber cores, and a processor (PROC, 14) determines the position and/or shape based on said measured strains from the plurality of optical fiber cores. The fiber Bragg grating(s) (FBG, 8) extends along the full length of said optical fiber cores (9), the fiber core having a spatially modulated reflection (r) along the said full length of the optical fiber core so that the corresponding reflection spectrum is detectable in said wavelength scan.

Abstract: The present invention is directed to an assembly for use in detecting an analyte in a sample based on thin-film spectral interference. The assembly comprises a waveguide, a monolithic substrate optically coupled to the waveguide, and a thin-film layer directly bonded to the sensing side of the monolithic substrate. The refractive index of the monolithic substrate is higher than the refractive index of the transparent material of the thin-film layer. A spectral interference between the light reflected into the waveguide from a first reflecting surface and a second reflecting surface varies as analyte molecules in a sample bind to the analyte binding molecules coated on the thin-film layer.

Abstract: A material sensing apparatus comprises an excitation source configured to induce waves in a workpiece, and an optical waveguide interferometer configured to sense the induced waves in the workpiece. The optical waveguide interferometer comprises a probe segment having a probe segment end, and an adjustable coupler configured to permit setting a gap between the probe segment end and the workpiece. A controller is coupled to the adjustable coupler and configured to set the gap between the probe segment end and the workpiece.

Abstract: A method and apparatus are provided for a swept source optical coherence tomography (OCT) system utilizing a fast scanning mechanism in the sample arm and a slowly swept light source. The position data is collected rapidly while the wavelength of the source is swept slowly. The system reduces the sweep speed requirements of the light source enabling higher power, greater imaging range, and linear sweeps of the source frequency. The OCT components (or most of them) may be implemented within a hand held imaging probe. In operation, a triangulation scan may be used to orient the imaging probe with respect to a fixed coordinate system; preferably, OCT data captured by the device is then transformed to that same orientation with respect to the fixed coordinate system to improve the scanning results.

Abstract: A system for measuring a shape of a target object includes a photonic integrated circuit and a light detector. The photonic integrated circuit includes a phase shifter configured to change a phase difference between a first portion of light and a second portion of light within the phase shifter, and an output element configured to output the light from the phase shifter directly toward the target object. The output element includes a first output waveguide configured to act as a first point source; and a second output waveguide configured to act as a second point source. The light detector is positioned to receive reflected light from the target object.

Abstract: A device for interferometric vibration measurement, having a radiation source for generating an original beam, a first beam splitter for dividing it into measuring and reference beams, a detector and a focusing device. The measuring beam at least partly reflected by the object and the reference beam are superimposed on a detection area of the detector, and the focusing device in the beam path of the measuring beam between the image unit and object focuses it onto a measuring point. Here, a measuring beam having a wavelength greater than 1100 nm is generated and the device has an image unit for two-dimensional imaging of the object surrounding the measuring point. The measuring beam focus lies in the focal plane of the image unit and, by use of the focusing device, the focal point of the measuring beam and the focal plane of the imaging unit are displaceable simultaneously.

Abstract: A device for interferometric imaging may comprise multiple optical elements arranged in a linear configuration. The device may also comprise multiple waveguide arrays (WGAs) each WGA of the multiple WGAs may include one or more WGs. Some of the WGs of each WGA of the multiple WGAs may be optically coupled to an optical element of the multiple optical elements. Each WG of a first WGA of the multiple WGAs is coupled to a first optical element of the multiple optical elements and is paired with a WG of a second WGA of the multiple WGAs that is coupled to second optical element of the multiple optical elements. The lengths of the paired WGs of the first and second WGAs of the multiple WGAs are not equal.

Abstract: Some embodiments of the present invention provide adapters for use in posterior imaging systems. The adapters include lens set configured to adapt the posterior imaging system to operate as an anterior imaging system. Related optical coherence tomography systems and anterior imaging systems are also provided herein.

Abstract: A method distributing data in a network is provided. The method comprises measuring the path lengths between a reference clock and a plurality of remote destinations and sending a timing signal from the reference clock to the plurality of remote destinations. The method further comprises measuring the phase between the reference clock and a return signal from each of the plurality of remote destinations and adjusting the phase of the data such that each remote destination receives the data within a skew tolerance.

Abstract: In one embodiment of the invention, a semiconductor optical amplifier (SOA) in a laser ring is chosen to provide low polarization-dependent gain (PDG) and a booster semiconductor optical amplifier, outside of the ring, is chosen to provide high polarization-dependent gain. The use of a semiconductor optical amplifier with low polarization-dependent gain nearly eliminates variations in the polarization state of the light at the output of the laser, but does not eliminate the intra-sweep variations in the polarization state at the output of the laser, which can degrade the performance of the SS-OCT system.

Abstract: An optical interferometer including an output-beam beam input for coupling-in an output beam, and a beam splitter device for splitting the output beam into at least one first sub-beam and one second sub-beam, the interferometer being embodied as a heterodyne interferometer by virtue of at least one optical frequency shifter being arranged in the beam path of the interferometer and the interferometer including one or more optical waveguide elements, by which optical waveguides are formed, at least between the output-beam beam input, beam splitter device and frequency shifter. The frequency shifter is arranged in the beam path of the first or second sub-beam.

Abstract: An optical device and a method of using an optical filter are provided. The optical device includes an optical filter and a narrowband optical source. The optical filter has a refractive index that varies along a length of the optical filter. The narrowband optical source is in optical communication with the optical filter and is configured to generate light having a wavelength at or in the vicinity of at least one of a wavelength corresponding to a local transmission maximum and a wavelength corresponding to a maximum slop of the group index spectrum of the optical filter.

Abstract: Disclosed herein is a system for measuring characteristics in a well bore. The system includes a fiber-optic wire extending along a length of the well bore a monitoring system. The monitoring system includes a swept-wavelength interferometer (SWI) configured to transmit light into the fiber-optic wire by sweeping the light across a range of wavelengths, and the monitoring system is configured to detect a characteristic in the well bore based on detecting a Rayleigh backscatter of the light transmitted into the fiber-optic wire.

Abstract: A system and method for the monitoring of ammonia in a fluid. The ammonia monitoring system includes an ammonia sensor that is configured to detect trace amounts of ammonia (NH3) in a fluid (i.e., gas or liquid) that is pumped through it in real time. The real time ammonia sensor includes an interferometer configured to track the amount of ammonia that is pumped into the real time ammonia sensor. The ammonia monitoring system, via the real time ammonia sensor, is further configured to detect ammonia levels in industrial poultry houses and provide electronic feedback to the building's ventilation control system.

Abstract: An optical analyzer performing analysis excellent in spatial resolution and in invasion depth is provided.

Abstract: An optical biosensor may include a biosensing unit, detection unit, and signal processing unit. The biosensing unit may be configured for receiving first and second optical signals (which are generated from a phase-modulated optical signal), outputting a sensing signal by transmitting the first optical signal via a first optical path that includes a sensing resonator, and outputting a reference signal by transmitting the second optical signal via a second optical path that includes a reference resonator. The detection unit may be configured for receiving the sensing signal and the reference signal, detecting a phase element of each of the sensing signal and the reference signal through a signal demodulation operation, and detecting a phase difference between the sensing signal and the reference signal according to the detected phase elements. The signal processing unit may be configured for calculating the concentration of a bio-material based on the detected phase difference.

Abstract: Systems and methods and apparatuses for characterizing near field transducer performance at wafer level using asymmetric interference waveguides are provided. One such system includes a light source, an input grating configured to receive light from the light source, a first waveguide arm and a second waveguide arm, each configured to receive the light, a surface plasmon receptor optically coupled to the first waveguide arm and the second waveguide arm and configured to receive light from the first waveguide arm in a first direction and the second waveguide arm in a second direction opposite of the first direction, where the first and the second waveguide arms are configured to induce a preselected phase difference in light arriving at the surface plasmon receptor, and an output grating optically coupled to the surface plasmon receptor, and a light detector coupled to, and configured to detect light from, the first output grating.

Abstract: A probe detachably connected to an optical measurement apparatus includes: a fiber that emits light by the optical measurement apparatus, and outputs reflected light and/or scattered light from an object to be measured; a covering member that covers a side face of the fiber; a cap that covers a distal end of the probe; a standard object that is provided on a surface of the cap facing the distal end of the fiber and that is used in calibration measurement by light emitted from the distal end of the fiber; an adhesive member that adheres the cap to the distal end of the probe and is made of an adhesive material; a heat-generating portion that generates heat to be applied to the adhesive member; and a thermal conduction portion that conducts heat that decreases the adhesive strength of the adhesive material with respect to the covering member.

Abstract: Optical communication systems are sensitive to chromatic dispersion. An optical interleaver structure is provided that provides a significantly reduced dispersion, obtained by using at least one of a proper coating and a desired phase offset of each interfering cavity.

Abstract: In certain embodiments, an optical device and a method of use is provided. The optical device can include a fiber Bragg grating and a narrowband optical source. The narrowband optical source can be configured to generate light. A first portion of light can be transmitted along a first optical path extending along and through the length of the fiber Bragg grating at a group velocity. The light can have a wavelength at or in the vicinity of a wavelength at which one or more of the following quantities is at a maximum value: (a) the product of the group index spectrum and a square root of the power transmission spectrum, (b) the slope of a product of the group index spectrum and one minus the power transmission spectrum, and (c) the slope of a product of the group index spectrum and the power transmission spectrum.

Abstract: An interferometer generates interference between two (or more) waves that have traveled separate paths so as to measure a quantity of difference between these paths. One of these paths, the reference path, is usually one with well known spatial and material properties (such as free 5 space). The other path(s) is(are) the test path(s). The main difficulties in interferometry stem from the production and operation of this physical reference path. The present invention solves this problem by replacing the physical reference path with a virtual one. This is done by suitable operation on the physically generated interference pattern of an unreferenced interferometer with a virtually generated sinusoid of frequency corresponding to the desired reference path length. The result is a new form of interferometer called a Virtual Reference Interferometer.

Abstract: A system for analysis of a fluid, comprises a light source for radiating a beam of light an optical path for guiding at least part of the beam of light, a fluidic channel for guiding the fluid along the optical path, and a detector for detecting an optical characteristic of the light having propagated along the optical path. The optical path comprises a multimode interference structure, the multimode interference structure being arranged for providing a propagation of the beam of light in at least two propagation modes, the detector being positioned so as to receive light from each of the at least two propagation modes.

Abstract: A photonics integrated system is disclosed, comprising a substrate, an integrated interferometer integrated in the substrate and being configured for receiving radiation from a radiation source, and an integrated spectral filter integrated in the substrate and being configured for receiving radiation from the interferometer. The integrated interferometer has a period and the integrated spectral filter has a bandwidth such that the period of the integrated interferometer is smaller than the bandwidth of the integrated spectral filter. The integrated spectral filter has a periodic transfer characteristic with a period and the system has a bandwidth such that the period of the periodic transfer characteristic of the integrated spectral filter is larger than the bandwidth of the system.

Abstract: Step-phase interferometers are provided for use as optical interleavers/de-interleaver for optical communication. High data rates require a wide band-width to pass the high-speed modulated optical spectrum, and further require a wide stop-band to reject the signal from adjacent channels. The present interferometers provide a steep slope at the transition from the passband to the adjacent stop-band, thereby enlarging the width of both the pass-band and stop-band.

Abstract: A system and method to obtain and process interferometer output scans is described. The interferometer-based sensor system includes a tunable laser to transmit a transmit signal and a polarization scrambler to produce a polarization state change on the transmit signal. The system also includes an interferometer to provide an output scan based on the transmit signal with the polarization state change and a processor to process the output scan.

Abstract: The general field of the invention is that of optical devices designed for measuring anemometer parameters such as speed and temperature, the device being mounted on an aircraft and comprising an optical emission module illuminating the outside air, an optical reception module capable of receiving the light scattered by the air molecules, optical means forming a reference path and computing means connected to the reception module. The optical reception module comprises optical mixing means for mixing a portion of the beam originating from the reference path and a portion of the scattered light beam. The optical emission and reception means are arranged so that the reception device collects the light originating from the Brillouin-Mandel'shtam scattering.

Abstract: A serial weak FBG interrogator is disclosed. The serial weak FBG interrogator may include a CW tunable laser or pulsed laser utilized as a laser source and an EDFA. The serial weak FBG interrogator may also be an interrogation of a single sensor system by utilization of a DFB laser which utilizes a single sensor, which may be an interferometer sensor, an extrinsic Fabry-Perot interferometer or a wavelength-modulated sensor. The serial weak FBG interrogator may also include a computer system or CSPU.

Abstract: A Mach-Zehnder interferometer (MZI) incorporates a tunable multimode interference (MMI) coupler comprising a tunable MMI coupler with a tuning electrode on a surface of a tunable MMI region and an electrically insulating region provided within the tunable MMI region. The MMI region is tunable in response to detection of a photocurrent by a photodetector section. Such a tunable MZI is particularly advantageous in enabling a split ratio of an optical splitter, the split ratio and the splitter to be controlled in a particularly efficient manner.

Abstract: An apparatus to detect a pressure signal in a fluid flowing in a conduit comprises a flexible band sized to fit at least partially around the conduit. An optical fiber is flexibly adhered to the flexible band. At least one fastener is attached to the flexible band to fasten the flexible band at least partially around the conduit. A method for detecting a pressure signal in a conduit comprises adhering an optical fiber to a flexible band. At least one fastener is attached to the band. The band is fastened around the conduit such that a strain induced in the conduit by the pressure signal is transmitted to the optical fiber.

Abstract: Systems and methods are described herein for a self-referencing interferometer. The interferometer can comprise an improved spatial phase shifter that reduces the number of components, size and complexity of the spatial phase shifter and maintains a common path for a combined reference beam and signal beam. The self-referencing interferometer further comprises a single mode fiber shunt for filtering the reference beam and further reducing the size of the interferometer. The angle of the reference beam can be tilted before being recombined with the single beam which further simplifies the spatial phase shifting component of the interferometer.

Abstract: Optical-based apparatus and method for sensing parameters in connection with an asset, such as a pipeline, are provided. At least two sites in an optical fiber may include a respective fiber grating arranged to have a respective optical response in a wavelength spectrum having a distinguishing feature indicative of a value of a respective local parameter at a respective grating site. The two fiber gratings may be further arranged to form, in combination with a respective portion of the optical fiber which extends between the two sites, respective optical backscatter portions that when combined with one another are effective to sense an optical change in the fiber portion between the sites indicative of a value of a distributed parameter. This is a parameter modality different from a parameter modality of the respective local parameters at the respective grating sites.

Abstract: The present subject matter relates to in vivo volumetric bidirectional blood flow imaging using single-pass flow imaging spectral domain optical coherence tomography. This technique uses a modified Hilbert transform algorithm to separate moving and non-moving scatterers within a depth. The resulting reconstructed image maps the components of moving scatterers flowing into and out of the imaging axis onto opposite image halfplanes, enabling volumetric bidirectional flow mapping without manual segmentation.

Abstract: A system and method for monitoring a structure and for distinguishing between an alarm condition, and a nuisance event such as rain. An optical fibre sensor (20,22) produces a signal indicative of a disturbance and level crossing rates are determined to distinguish between noise in the signal (nuisance event) and a required event. A FFT technique is also disclosed as well as classification of an event by extracting predetermined features from the signal.