Distributed fiber sensor with detection and signal processing using polarization state management
First Claim
1. An apparatus for detecting and locating a disturbance, comprising:
- at least one light source;
an optical system comprising at least one optical waveguide, the optical waveguide having at least one detection zone defining a length, wherein the disturbance can occur at any place in the detection zone;
wherein the optical system is configured to carry signals along at least two counter-propagating optical channels;
at least one beam separator coupled to the optical system, wherein the beam separator develops at least two beams coupled into said two counter-propagating optical channels, respectively;
at least one polarization sensitive beam combiner operative selectively to combine polarization components of said at least two beams traveling along the optical waveguide, the polarization sensitive beam combiner being coupled to the optical waveguide so as to act upon at least one of said two counter-propagating optical channels, where said at least one of said two counter-propagating optical channels is propagating in a direction that is one of toward the detection zone and away from the detection zone;
at least one polarization sensitive detector coupled to the optical waveguide;
a data processing unit coupled to the polarization sensitive detector, the data processing unit being operable to localize the place of the disturbance in the detection zone.
1 Assignment
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Accused Products
Abstract
Polarization effects are managed to provide differential timing information for localizing disturbances affecting two or more counter-propagating light signals on one or more optical waveguides passing through a detection zone. Activity can be localized to a point for a security perimeter. Events causing optical disturbance can be mapped to points along a straight line, a perimeter or arbitrary pattern or an array. Events cause local changes in optical properties in the optical waveguide, in particular an optical fiber. Short term local changes are distinguishable from phase changes of light travel in the waveguide, by managing the polarization state of input and output beams, combining orthogonal polarization components and other aspects. The changes in the states of polarization of the counter-propagating light signals are determined and the temporal spacing of corresponding changes in polarization state are resolved to pinpoint the location of the event along the optical fiber.
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Citations
70 Claims
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1. An apparatus for detecting and locating a disturbance, comprising:
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at least one light source;
an optical system comprising at least one optical waveguide, the optical waveguide having at least one detection zone defining a length, wherein the disturbance can occur at any place in the detection zone;
wherein the optical system is configured to carry signals along at least two counter-propagating optical channels;
at least one beam separator coupled to the optical system, wherein the beam separator develops at least two beams coupled into said two counter-propagating optical channels, respectively;
at least one polarization sensitive beam combiner operative selectively to combine polarization components of said at least two beams traveling along the optical waveguide, the polarization sensitive beam combiner being coupled to the optical waveguide so as to act upon at least one of said two counter-propagating optical channels, where said at least one of said two counter-propagating optical channels is propagating in a direction that is one of toward the detection zone and away from the detection zone;
at least one polarization sensitive detector coupled to the optical waveguide;
a data processing unit coupled to the polarization sensitive detector, the data processing unit being operable to localize the place of the disturbance in the detection zone. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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- 22. The apparatus of 1, further comprising at least one polarization controller operable for altering a polarization of the waveguide.
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40. An apparatus for detecting and locating a disturbance, comprising:
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at least one light source;
an optical system comprising an optical waveguide, the optical waveguide having at least one detection zone defining a length, wherein the disturbance can occur at any place in the detection zone;
wherein the optical system is configured to carry signals along at least two counter-propagating optical channels;
at least one polarization sensitive beam combiner operative selectively to combine polarization components of said at least two beams traveling along the optical waveguide, the polarization sensitive beam combiner being coupled to the optical waveguide so as to act upon at least one of said two counter-propagating optical channels, where said at least one of said two counter-propagating optical channels is propagating in a direction that is one of toward the detection zone and away from the detection zone;
at least one polarization sensitive detector coupled to the optical waveguide;
a data processing unit coupled to the polarization sensitive detector, the data processing unit being operable to localize the place of the disturbance in the detection zone.
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41. An apparatus for detecting and locating a disturbance, comprising:
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at least one light source;
at least one optical switch operable to couple the light source to at least one of a plurality of optical sub-systems, wherein the optical sub-systems each comprise at least one optical waveguide, and each define at least one detection zone having at least one of a length and width over which the disturbance can occur and thereby detectably affect the optical waveguide, wherein at least an active subset of said optical sub-systems carries at least two counter-propagating optical channels when operatively coupled to the light source;
at least one beam separator operatively coupled to the active subset of the optical systems, wherein the beam separator develops at least two beams that are coupled into the counter-propagating optical channels;
at least one polarization sensitive beam combiner operative selectively to combine polarization components from at least one of said at least two beams, the polarization sensitive beam combiner being coupled to the optical waveguide so as to act upon at least one of said two counter-propagating optical channels propagating in a direction that is one of toward the detection zone and away from the detection zone;
wherein the beams coupled into the counter-propagating optical channels are further coupled to at least one polarization sensitive detector for sensing said beams as affected by the disturbance;
a data processing unit coupled to the polarization sensitive detector, the data processing unit being operable to localize the place of the disturbance in the detection zone.
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42. A method for detecting and localizing a disturbance, comprising:
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applying at least one light source to an optical system having at least one optical waveguide, the optical waveguide having at least one detection zone defining a length, wherein the disturbance can occur at any place in the detection zone and the optical system is configured to carry signals along at least two counter-propagating optical channels that traverse the detection zone;
separating at least one beam from the light source into at least two beams, and coupling the two beams into counter-propagating optical channels of the at least one optical waveguide so as to traverse the detection zone;
selectively combining polarization components of said at least two beams traveling along the optical waveguide, using a polarization sensitive beam combining technique upon at least one of said two counter-propagating optical channels, in a direction that is one of toward the detection zone and away from the detection zone;
detecting a polarization attribute of said at least two beams after traversing the detection zone, said polarization attribute being affected by the disturbance; and
,determining from a timing relationship of the polarization attribute for said at least two beams, a place in the detection zone corresponding to the disturbance. - View Dependent Claims (43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70)
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Specification