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: 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: 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: 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: 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: 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: 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: 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 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: 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: 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: 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: 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: An optical sensor (10) comprises an optical cavity defined by a dielectric body and responsive to one or more physical environmental conditions, and a waveguide (70) having a terminal end spaced apart from the optical cavity such that light is optically coupled from the terminal end of the waveguide (70) to the optical cavity. The waveguide (70) is arranged such that, in use, it is maintained at a first temperature that would not damage the optical coupling to the optical cavity when the dielectric body is maintained at a second temperature sufficient to damage the optical coupling to the optical cavity.

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.

Abstract: Provided is a chromatic dispersion measurement device including a light branching unit that divides a incident measured light signal into a first measured light signal and a second measured light signal and causes a frequency difference between the first measured light signal and the second measured light signal when the signals are output, an optical phase shifter provided in either one of the first branch path and the second branch path having a polarization maintaining characteristic and periodically changing a phase ?i of the measured light signal, an optical combination unit that combines the first measured light signal and the second measured light signal and outputs an interference element of an i-th optical component obtained by interference of the first measured light signal and the second measured light signal when the phase difference is the phase ?i, as a combined measured light signal.

Abstract: A sensing apparatus comprises an excitation source configured to induce waves in a target, and a fiber optic interferometer configured to sense the induced waves in the target. The fiber optic 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 target. A controller is coupled to the adjustable coupler and configured to set the gap between the probe segment end and the target.

Abstract: A non-contact sensing system for measuring and analyzing an object's position, motion, and/or resonance utilizes optical capturing of image features, data extraction, and signal processing to determine changes in the object's motion or position according to changes in signals, which are associated with the excitation of photons due to the object's motion.

Abstract: Problems To provide a method for evaluating characteristics of MZ interferometers in an optical modulator having a plurality of MZ interferometers. Means for Solving Problems When an optical modulator includes a plurality of MZ interferometers, the 0-degree component contains a signal derived from an MZ interferometer other than the MZ interferometers for evaluating the characteristic. For this, it is impossible to accurately evaluate the characteristic of the MZ interferometers. The present invention does not use the 0-degree component normally having the highest intensity. That is, the characteristic of the MZ interferometers are evaluated by using a side band intensity of the component other than the 0-degree component.

Abstract: An OCT system and method with integrated pressure measurement. In one embodiment, the system includes an interferometer; a wavelength swept laser; a source arm in communication with the wavelength swept laser; a reference arm in communication with a reference reflector; a first photoreceiver having a signal output; a detector arm in communication with the first photoreceiver, a probe interface; a sample arm in communication with a first optical connector of the probe interface; an acquisition and display system comprising: an A/D converter having a signal input in communication with the first photoreceiver signal output and a signal output; a processor system in communication with the A/D converter signal output; and a display in communication with the processor system; and a probe comprising a pressure sensor and configured for connection to the first optical connector of the probe interface, wherein the pressure transducer comprises an optical pressure transducer.

Abstract: An apparatus, method and computer program wherein the apparatus includes at least one interferometer where the at least one interferometer is configured to cause interference of an electromagnetic input signal; wherein the at least one interferometer is configured to receive at least one sensor input signal from at least one sensor such that the sensor input signal controls the interference of the electromagnetic input signal by the at least one interferometer; wherein the at least one interferometer is configured to provide a plurality of outputs where each of the plurality of outputs is provided by the at least one interferometer responding to the at least one sensor input signal with a different sensitivity; and at least one detector configured to detect the plurality of outputs of the at least one interferometer and provide a digital output signal indicative of the at least one sensor input signal.

Abstract: The invention relates to an optical sensor arrangement comprising a measuring optical fiber demonstrating birefringence modifiable as a function of a measurement variable, and to an optical analysis unit having two optical branches implemented as optical fibers forming a Mach-Zehnder interferometer and an optical coupler for bringing together light guided in the two branches, wherein at least one output of the coupler is optically connected to at least one light-sensitive element, and wherein the analysis unit comprises a polarizing beam splitter from which the optical branches originate, wherein the measurement optical fiber is connected upstream of an optical input of the polarizing beam splitter, and wherein a polarization converter is disposed in a course of one of the optical branches. The invention further relates to a detection method that can be performed using said sensor arrangement.

Abstract: A sensor (10) and corresponding method for sensing variations in a parameter employ an optical device (12) defining two optical paths (14, 16) differentially affected by a variation in the parameter so as to change the differential phase between the two paths. This differential phase is monitored by a spectral interrogation arrangement (18) including a radiation input device (20) for delivering to the optical device (12) incident radiation at a plurality of wavelengths, and a reading arrangement (22) for measuring the interference-modulated optical output. The optical device (12) is configured so that the two optical paths have differing dispersion properties such that a difference between the phase accumulated by light propagating along the optical paths as a function of wavelength exhibits a maximum or minimum at some wavelength designated ?critical. The plurality of wavelengths employed by the spectral interrogation arrangement span a range of wavelengths including, or adjacent to, ?critical.

Abstract: An optical device includes first and second optical branches. The first optical branch is formed at an interface between a first substrate and a second substrate, and the second optical branch is formed at an interface between the second substrate and an ambient medium. The second substrate defines first and second spaced apart slits that are each coupled to the first and second optical branches. The first slit is configured to receive at least partially coherent light from a light source and in response excite at least one surface plasmon polariton mode in each of the first and second optical branches. The second slit is configured to combine the surface plasmon polariton modes received from the first and second optical branches and emit scattered light into at least one of the first substrate and the ambient medium.

Abstract: Provided is a phase shift interferometer which comprises: a light source; an incident light path; a light circulation unit; a connection path; a light splitting/combining unit; a probe light path; a reference light path; a test sample measurement unit; a light terminal; a light-phase shifting unit which is provided in either the probe light path or the reference light path, and subjects light to phase shifting by a phase shift quantity of ?i/2 (radian units, where ?i is a real number, the range of values taken by ?i is 0??i?3?/2, and i is an integer where 3?i), and periodically changes the phase shift quantity of ?i/2; a light-emission path; a light detector which outputs an interference signal; and a controller for controlling the phase shift quantity in the light-phase shifting unit and the cycle at which the phase shift is controlled.

Abstract: The wavelength control device comprises a first Mach-Zehnder filter which receives a first optical signal and outputs an optical signal having a predetermined wavelength, a second Mach-Zehnder filter which receives a second optical signal and outputs an optical signal having a predetermined wavelength, a heating unit heating respective parts of either one of the waveguides of the first and second Mach-Zehnder filters, a first wavelength detecting unit which receives an optical signal from the first Mach-Zehnder filter and detects a wavelength thereof, a second wavelength detecting unit which receives an optical signal from the second Mach-Zehnder filter and detects a wavelength thereof, a power control unit which controls power supplied to the heating unit based on the wavelength received from the first wavelength detecting unit, and an output unit which outputs a wavelength value based on the wavelength received from the second wavelength detecting unit.

Abstract: The present invention provides for the detection and display of polarization scrambling tissue without resolving the polarization state of the backscattered imaging beam. In one embodiment, we illuminate the tissue using two different polarizations. A first polarization determines a first image of high intensity while the second polarization determines a second image of low intensity. Comparison and combination of the first and second images determines tissue which scrambles the polarization in neighboring detection cells.

Abstract: A Fiber-optic current sensor for sensing electric current carried in an electric conductor (18). Its optical section comprises: a light source (1); a directional coupler (2) with two ports (2A, 2B) of two arms each; a radiation polarizer (3); a polarization modulator (4); a fiber line (17) coupled to a current-sensing fiber loop (11); a mirror (10); and a photodetector (22). The first port of the coupler (2) is coupled to the light source (1) and to the photodetector (22). Its second port is coupled via the radiation polarizer (3) to the polarization modulator (4). The polarization modulator comprises a magneto-sensitive element (5), around which a solenoid (6) is wound. The fiber loop (11) comprises a magneto-sensitive optical fiber with embedded linear birefringence. An electronic section comprises a signal generator (21) which drives the solenoid (6); and a signal processing unit which receives the optical signal from the photodetector (22).

Abstract: An apparatus for estimating a parameter includes: an optical fiber including at least one core configured to transmit an interrogation signal and including a plurality of sensing locations distributed along a measurement length of the optical fiber and configured to reflect light; a reference optical path configured to transmit a reference signal, the reference optical path disposed in a fixed relationship to the at least one core and extending at least substantially parallel to the at least one core, the reference optical path including a reference reflector that defines a cavity length corresponding to the measurement length; a detector configured to receive a reflected return signal; a reference interferometer configured to receive at least a reference signal and generate an interferometric reference signal; and a processor configured to apply the interferometric reference signal to the reflected return signal to compensate for one or more environmental parameters.

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