Nederlandse Organisatie Voor Toegepast-natuurwetenschappelijk Onderzoek Tno

Asml Netherlands B.v.

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Lun Kai Cheng

Peter Martijn Toet

Arjen Boersma

Theodorus Henricus Cornelus Panken

Arno Willem Frederik Volker

Huibert Blokland

Nicolaas Antonius Allegondus Johannes Van Asten

Luberthus Ouwehand

Elke Van Loenhout

Alexander Charles Franciscus Anna Van Well

Hans Baltus Bakker

Machiel Jacobus Johannes Viguurs

Oana Cristina Balan

Franciscus Johannes Joseph Janssen

Tjarko Adriaan Rudolf Van Empel

Paul Louis Maria Joseph Van Neer

Fokko Pieter Wieringa

Marcel Johannus Elisabeth Hubertus Muitjens

Michiel Peter Oderwald

Gert-Jan Adriaan Van Groenestijn

Evert Nieuwkoop

Roger Wilhelmus Antonius Henricus Schmitz

Frederik Van Der Graaf

Richard Versluis

Johannes Fransiscus Maria Velthuis

Axel Sebastiaan Lexmond

Paulus Bartholomeus Johannes Schaareman

Erwin Johannes Martinus Giling

Hendrik De Man

Marinus Carolus Adrianus Maria Peters

Wouter Schiferli

Hendrik Rendering

Remco Alexander Nieuwland

Rik Jansen

Ronald Antonius Jan Hagen

Mathilde Gertrudis Maria De Kroon

Tatiana Johanna Judith Teerling

Martinus Henricus Johannes Lemmen

Charles William Barras Potts

Oana Elena Van Der Togt

Willem Arie Van Helden

Kristiaan Albert Broekens

Dick Bruijn

Edward Jacobus Johannes Doppenberg

Marinus Carolus Peters

An interferometer suitable for Distributed Acoustic Sensing (DAS) is has two interferometer arms of different length, from which light is fed to an N-way optical coupler (N at least 2). In DAS, the light is backscattered light received from within an optical fiber. Incoming light is amplified by an adjustable factor, which may vary as a function of time in DAS. The N way optical coupler supplies combinations of light from the arms with different relative phase offsets to each other to N outputs. Phase shift between interfering components is computed from the light intensities detected by detectors at the N outputs. Correction of the computed phase shift is applied dependent on the value of the adjustable amplification factor. For this, one interferometer arm comprises a phase modulator, which is used obtaining measured detector output signals from the detectors with different phase shifts by the phase modulator when the value of the adjustable factor is used. Data is determined that defines average of output signals of the different detectors under variation of different phase shift by the phase modulator based on the measured signals. For DAS, data defining time dependent averages according the variation of the factor are determined. A phase shift between interfering light is computed with a correction to compensate for differences between the average detector output signals for the individual optical detectors.

Method and system for determining a phase shift between components of variably amplified light

Ultrasonic measurements of fluid properties are performed with the aid of an optical fiber or a package of optical fibers by exciting ultrasound waves at a first location along the optical fiber in the fluid by means of light from the optical fiber and detecting an effect of the ultrasound waves on light reflection or propagation in the optical fiber and/or a further optical fiber in the package at a second location along the optical fiber or at the end of the optical fiber.

Device and method for performing ultrasonic measurements of fluid properties

Translations of an object in a plurality of different spatial directions are measured using a plurality of interferometers to detect interference with light that has been reflected from a diffusively reflective surface, preferably using diffuse reflection from the same planar surface to measure in each of the different spatial directions. At least the interferometers that measure translation in directions that are not perpendicular to the surface each comprises a single mode fiber and a collimator configured to transmit the outgoing light to the object successively through the single mode fiber and the collimator, and to collect reflection into the single mode fiber with the collimator both along a same beam direction. It has been found that, when reflection of a beam with a beam direction at an oblique angle to a diffusively reflective surface is used, the interference resulting from translation of the object is due substantially only to translation in the beam direction.

Device and method for interferometric measurement of a two or three dimensional translation of an object

A laser device for optical communication comprises a first laser unit connected to a first optical fiber for supplying a transmission laser beam thereto. wherein the laser device is configured for providing a reference laser beam in addition to the transmission laser beam. For providing the reference laser beam the laser device further includes a second laser unit connected to a second optical fiber for supplying the reference laser beam to the second optical fiber. The first laser unit is configured for providing the transmission laser beam as a linear polarized beam that is polarized in a first polarization direction, and the second laser unit is configured for providing the reference laser beam as a linear polarized beam that is polarized in a second polarization direction. The first optical fiber and the second optical fiber are formed of polarization maintaining optical fibers, and the laser device further includes a polarization combiner connected to a third polarization maintaining optical fiber for conveying the transmission laser beam and the reference laser beam to an optical output of the laser device.

Laser device for optical communication, optical communication system and use of these

A fiber optic sensor device comprising an optical fiber with a multilayer coating on the optical fiber at least in a fiber section of the optical fiber. The multilayer coating comprises a chrome layer on the optical fiber, a metal layer such as a copper layer on the chrome layer and an indium or lead layer on the metal layer. The indium or lead layer having a thickness larger than thicknesses of the chrome and metal layers, preferably with a thickness about equal to the radius of the optical fiber.

Cryogenic fiber optic sensor device

Local strain and optionally other properties of an optical sensing fiber are detected as a function of position along the optical sensing fiber. A light pulse with a plurality of simultaneous laser modes at mutually different wavelengths is transmitted into the optical sensing fiber. Light produced by backscattering of the light pulse in the optical fiber is fed to a multi-way coupler, via a first and second optical path with different optical path lengths. Intensities of different phase combinations of light from the paths are detected by detectors at the outputs of the multiway coupler. A data processing system computes relative phase values of light from the first and second paths for a series to time points with time delays corresponding to scattering at different positions along the fiber. In an embodiment, inelastically scattered light such as due to Brillouin scattering and/or Raman scattered light is selective passed to the detectors and detected.

Detection of local property changes in an optical sensing fiber

An optical sensor interrogation system can have a light source arranged for emitting light; a first optical arrangement arranged for intercepting the light and to forward the light to an optical sensor and to receive light therefrom. The wavelength reference is adapted to provide a reference wavelength. The system can further have a second optical arrangement adapted to receive reflected light from the optical sensor, a lens system for transferring the light into a beam and a scanning assembly including a scanning unit and/or a diffractive optical element. The system can still further have a detector for receiving optical response from the scanning assembly and a data processing system. A method is used to manufacture an optical sensor interrogation system.

Optical sensor interrogation system a method of manufacturing the optical sensor interrogation system

Distance to a target is sensed using a common path interferometer, wherein a first fraction of light from a light source is collected after reflection by a partially reflective element together with reflection from a target of a second fraction of light from the light source that has been transmitted by the partially reflective element. The collected light is split in two parts, both containing a part of the first fraction and part of the reflection from the target. The parts are fed through a first and second optical branch path to an input side of a three-way optical coupler respectively. Light from at three terminals on a second side of the N way coupler is fed to respective light intensity detectors. Information representing an excess distance traveled by the first fraction from detection signals determined by the least three light intensity detectors.

Interferometric distance sensing device and method with less dependency on environment disturbances on a fiber

A pressure sensing assembly (), comprising: an elongate, axially extending tube (), having a flexible tube wall () that encloses an inner pressure chamber (); and at least one sensor unit (), including: two tube wall fixation devices (), connected to the tube wall () at respective axially spaced apart positions, and configured to fix respective diameters (D, d) of the tube wall at said positions; and a first strain sensing element (), connected to the tube wall () at a first position axially in between said two tube wall devices (), and configured to provide a first signal indicative of an axial elongation of the tube wall resulting from a change in axial curvature of the tube wall when a pressure differential between the inner pressure chamber () and an outside environment () of the tube is applied across the tube wall at said first position.

Pressure sensing assembly

The invention relates to a sensor system comprising a waveguide, which waveguide comprises a grating in at least a part of the waveguide, which waveguide further comprises a coating, the coating comprising a polymer, which polymer comprises a chain, in which chain are present an aromatic group and a chemical group selected from the group of sulfonyl groups, carbonyl groups, carbonate groups, fluorocarbon groups, siloxane groups, pyridine groups and amide groups.

Distributed optical chemical sensor

A transversal load insensitive optical waveguide includes a primary section having a core. The waveguide may further include an outer cladding. The primary section includes a primary section surface and the outer cladding includes an exterior surface mechanically attached to the primary section surface by an interior cladding structure forming a mechanical connection. The cladding structure is such that for at least part of a distance between each two radial corresponding points on the exterior surface and the primary section surface respectively, the mechanical connection deviates from being radial, so that a radially-directed load on an exterior surface of the outer cladding is deflected by the cladding structure.

Transversal load insensitive optical waveguide, and optical sensor comprising a wave guide

A method for thermally conditioning an optical element includes irradiating the optical element with radiation, not-irradiating the optical element with the radiation, allowing heat flow between the optical element and a conditioning fluid that is held in a conditioning fluid reservoir, and providing a fluid flow of the conditioning fluid, to supply thermally conditioned fluid to the reservoir. A flow rate of the fluid during the irradiating of the optical element is lower than a flow rate of the fluid when the optical element is not-irradiated.

Method and system for thermally conditioning an optical element

The invention relates to a waveguide, comprising a grating in at least a part of the waveguide, which waveguide comprises a coating, the coating comprising a polymer, which polymer comprises an aliphatic chain, which aliphatic chain is provided with hydrophilic side-chains. The invention further relates to a sensor system comprising a waveguide according to any one of the preceding claims, a light source, and a photo-detector.

Coated waveguide for optical detection

An assembly comprising a fluid channel and a flowmeter, the flowmeter () comprising at least one vortex shedder () extending in the channel (C), each vortex shedder () being configured to generate Karman vortices (V) in fluid flowing through the channel (C) during operation, wherein each vortex shedder () is provided with a first fiber Bragg grating (FBG) of a fiber Bragg grating sensor (, FBG), wherein a Karman vortex frequency (fe) of the vortices (V) generated by the vortex shedder () is detectable utilizing a fiber Bragg grating (FBG) sensor signal relating to the respective first fiber Bragg grating (FBG) of that vortex shedder ().

Karman vortex flowmeter assembly comprising a fiber bragg grating sensor and method to measure a fluid flow rate

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Krimpen A/D Ijssel, Netherlands

Lun Kai Cheng