Fiber optic sensing apparatus including fiber gratings and method for sensing parameters involving different parameter modalities
First Claim
1. An apparatus comprising:
- an optical fiber comprising;
at least two grating sites in the optical fiber comprising respective fiber gratings arranged to have respective optical responses in a first wavelength range comprising a distinguishing feature, wherein the distinguishing feature is indicative of a value of a respective local parameter at a respective grating site;
wherein the fiber gratings are further arranged to form, in combination with a respective portion of the optical fiber which extends between said at least two grating sites, respective optical backscatter portions that when combined with one another define another distinguishing feature in the optical response in a second wavelength range that is effective to sense an optical change in the fiber portion between the sites indicative of a value of a distributed parameter, wherein the distributed parameter comprises a parameter modality different from a parameter modality of respective local parameters at the respective grating sites, and wherein the optical responses from one or more grating sites of the at least two grating sites and optical responses from the respective optical backscatter portions of the one or more grating sites are simultaneously processed to contemporaneously obtain sensing information representative of the local parameters and distributed parameters;
an optical interrogator operatively coupled to the optical fiber, the optical interrogator comprising;
a first detection channel configured to monitor the distinguishing feature indicative of the value of the respective local parameter at the respective grating site, wherein the first detection channel comprises;
a time division modulator arranged to relate one or more respective reflected pulses to one or more respective grating sites;
a spectrometer arranged to detect changes in the feature indicative of the value of a respective local parameter at a respective grating site; and
a second detection channel configured to combine the respective optical backscatter portions to sense the optical change in the respective fiber portion which extends between the two grating sites, wherein the optical change is indicative of the value of the distributed parameter.
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Accused Products
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.
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Citations
25 Claims
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1. An apparatus comprising:
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an optical fiber comprising; at least two grating sites in the optical fiber comprising respective fiber gratings arranged to have respective optical responses in a first wavelength range comprising a distinguishing feature, wherein the distinguishing feature is indicative of a value of a respective local parameter at a respective grating site; wherein the fiber gratings are further arranged to form, in combination with a respective portion of the optical fiber which extends between said at least two grating sites, respective optical backscatter portions that when combined with one another define another distinguishing feature in the optical response in a second wavelength range that is effective to sense an optical change in the fiber portion between the sites indicative of a value of a distributed parameter, wherein the distributed parameter comprises a parameter modality different from a parameter modality of respective local parameters at the respective grating sites, and wherein the optical responses from one or more grating sites of the at least two grating sites and optical responses from the respective optical backscatter portions of the one or more grating sites are simultaneously processed to contemporaneously obtain sensing information representative of the local parameters and distributed parameters; an optical interrogator operatively coupled to the optical fiber, the optical interrogator comprising; a first detection channel configured to monitor the distinguishing feature indicative of the value of the respective local parameter at the respective grating site, wherein the first detection channel comprises; a time division modulator arranged to relate one or more respective reflected pulses to one or more respective grating sites; a spectrometer arranged to detect changes in the feature indicative of the value of a respective local parameter at a respective grating site; and a second detection channel configured to combine the respective optical backscatter portions to sense the optical change in the respective fiber portion which extends between the two grating sites, wherein the optical change is indicative of the value of the distributed parameter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A pipeline comprising an apparatus, wherein the apparatus comprises:
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an optical fiber comprising; at least two grating sites in the optical fiber comprising respective fiber gratings arranged to have respective optical responses in a first wavelength range comprising a distinguishing feature, wherein the distinguishing feature is indicative of a value of a respective local parameter at a respective grating site; wherein the fiber gratings are further arranged to form, in combination with a respective portion of the optical fiber which extends between said at least two grating sites, respective optical backscatter portions that when combined with one another define another distinguishing feature in the optical response in a second wavelength range that is effective to sense an optical change in the fiber portion between the sites indicative of a value of a distributed parameter, wherein the distributed parameter comprises a parameter modality different from a parameter modality of respective local parameters at the respective grating sites, and wherein the optical responses from one or more grating sites of the at least two grating sites and optical responses from the respective optical backscatter portions of the one or more grating sites are simultaneously processed to contemporaneously obtain sensing information representative of the local parameters and distributed parameters; an optical interrogator operatively coupled to the optical fiber, the optical interrogator comprising; a first detection channel configured to monitor the distinguishing feature indicative of the value of the respective local parameter at the respective grating site wherein the first detection channel comprises; a time division modulator arranged to relate one or more respective reflected pulses to one or more respective grating sites; a spectrometer arranged to detect changes in the feature indicative of the value of a respective local parameter at a respective grating site; and a second detection channel configured to combine the respective optical backscatter portions to sense the optical change in the respective fiber portion which extends between the two grating sites, wherein the optical change is indicative of the value of the distributed parameter.
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18. An optical-based method for sensing parameters comprising:
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providing an optical fiber; arranging at least two grating sites in the optical fiber comprising respective fiber gratings arranged to have respective optical responses in a first wavelength range comprising a distinguishing feature, wherein the distinguishing feature is indicative of a value of a respective local parameter at a respective grating site; configuring the two fiber gratings to form, in combination with a respective portion of the optical fiber which extends between said at least two sites, respective optical backscatter portions that when combined with one another with one another define another distinguishing feature in the optical response in a second wavelength range that is effective to sense an optical change in the fiber portion between the sites indicative of a value of a distributed parameter, wherein the distributed parameter comprises a parameter modality different from a parameter modality of respective local parameters at the respective grating sites, and wherein the optical responses from one or more grating sites of the at least two grating sites and optical responses from the respective optical backscatter portions of the one or more grating sites are simultaneously processed to contemporaneously obtain sensing information representative of the local parameters and distributed parameters; monitoring the distinguishing feature indicative of the value of the respective local parameter at the respective grating site using a first detection channel of an optical interrogator wherein the first detection channel comprises; a time division modulator arranged to relate one or more respective reflected pulses to one or more respective grating sites; a spectrometer arranged to detect changes in the feature indicative of the value of a respective local parameter at a respective grating site; and combining the optical backscatter portions to sense the optical change in the respective fiber portion which extends between the two grating sites indicative of the value of a distributed parameter using a second detection channel of the optical interrogator. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25)
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Specification