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公开(公告)号：US20210318500A1
公开(公告)日：2021-10-14
申请号：US17259633
申请日：2019-07-12
摘要： 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.
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公开(公告)号：US20220026251A1
公开(公告)日：2022-01-27
申请号：US17413350
申请日：2019-12-16
发明人： Gert-Jan Adriaan VAN GROENESTIJN , Paul Louis Maria Joseph VAN NEER , Fokko Pieter WIERINGA , Arno Willem Frederik VOLKER , Lun Kai CHENG
IPC分类号： G01F1/66
摘要： 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.
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公开(公告)号：US20210389118A1
公开(公告)日：2021-12-16
申请号：US17270376
申请日：2019-08-26
摘要： 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.
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公开(公告)号：US20180299256A1
公开(公告)日：2018-10-18
申请号：US15764977
申请日：2016-10-03
摘要： The thickness of an at least partially transparent layer is measured using wavelength band limited light, with a coherence length that is less than twice the thickness of the layer. Reflections from layer are fed to a 2-n coupler (n>2) via optical transmission paths of different optical length. The 2-n coupler mix light from the path into n combinations of light from the paths, each combination with a different mutual phase offset between the light from the two paths. This leads to coherent interference between reflections from the front and back of the layer when the difference between the optical lengths of the optical transmission paths compensates for the path between reflection from the front and the back. A processing circuit computes information indicative of a phase difference between the reflections from n intensities of the 2-n coupler. The use of n>2 signals makes it possible to eliminate the influence of reflection amplitude variations on the computed phase difference.
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公开(公告)号：US20170350735A1
公开(公告)日：2017-12-07
申请号：US15538789
申请日：2015-12-23
IPC分类号： G01D5/353
CPC分类号： G01D5/35358 , G01D5/35329
摘要： 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.
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6.发明公开公开(公告)号：US20240175725A1
公开(公告)日：2024-05-30
申请号：US18284505
申请日：2022-03-31
CPC分类号： G01D5/35306 , G01D5/35361 , G01H9/004
摘要： 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.
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公开(公告)号：US20180356262A1
公开(公告)日：2018-12-13
申请号：US15778767
申请日：2016-11-25
摘要： 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.
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