Sensing device having a multicore optical fiber as a sensing element
First Claim
1. In a sensing device having a sensing element including an optical fiber, means for coupling light into the fiber and means for measuring alterations in specific physical parameters of the light passing through the fiber to determine special physical influences applied to the fiber, the improvements comprising the fiber being a multicore fiber having at least two adjacently extending cores surrounded by a common cladding and one end with an end face provided with a mirror so that light traveling in the cores is reflected at said one end to traverse the cores in the opposite direction;
- and said means for measuring the alterations in the parameters measuring the changes in the light passing through each of the cores in response to deformation of the fiber.
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Accused Products
Abstract
A sensing device which includes a sensing element in the form of an optical fiber, a device for coupling light into the fiber and a device for measuring changes in the specific physical parameters of the light passing through the fiber to determine special physical influences applied to the fiber characterized by the fiber being a multicore fiber having at least two adjacently extending cores surrounded by a common cladding and the means for measuring the changes in the parameter of the light measuring the alterations in the light passing through each of the cores. To make the device sensitive to bending and deformation in all directions, the fiber may have two cores and be twisted through 90° or the fiber may have three or more cores which are not disposed in the same plane. The measuring of the amount of change may be by measuring the interference pattern from superimposed beams of the output from the two cores or by measuring the intensity of each of the output beams separately.
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Citations
17 Claims
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1. In a sensing device having a sensing element including an optical fiber, means for coupling light into the fiber and means for measuring alterations in specific physical parameters of the light passing through the fiber to determine special physical influences applied to the fiber, the improvements comprising the fiber being a multicore fiber having at least two adjacently extending cores surrounded by a common cladding and one end with an end face provided with a mirror so that light traveling in the cores is reflected at said one end to traverse the cores in the opposite direction;
- and said means for measuring the alterations in the parameters measuring the changes in the light passing through each of the cores in response to deformation of the fiber.
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2. In a sensing device having a sensing element including an optical fiber, means for coupling light into the fiber and means for measuring alterations in specific physical parameters of the light passing through the fiber to determine special physical influences applied to the fiber, the improvements comprising the fiber being a multicore fiber having at least two adjacently extending cores surrounded by a common cladding, said multicore fiber being twisted about its longitudinal axis so that the device is permanently sensitive to deformation in any direction;
- and said means for measuring the alterations in the parameters measuring the changes in the light passing through each of the cores in response to deformation of the fiber.
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3. In a sensing device having a sensing element including an optical fiber, means for coupling light into the fiber and means for measuring alterations in specific physical parameters of the light passing through the fiber to determine special physical influences applied to the fiber, the improvements comprising the fiber being a multicore fiber having at least two adjacently extending cores surrounded by a common cladding, said adjacently extending cores being spaced apart a sufficient distance in the fiber so that no appreciable cross-coupling occurs therebetween;
- and said means for measuring the alterations in the parameters measuring the changes in the light passing through each of the cores in response to deformation of the fiber, said means for measuring including means for superimposing the beams of light emitted from each of the cores into at least one superimposed beam and a light-receiving surface disposed in said superimposed beam.
- View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. In a sensing device having a sensing element including an optical fiber, means for coupling light into the fiber and means for measuring alterations in specific physical parameters of the light passing through the fiber to determine special physical influences applied to the fiber, the improvement comprising the fiber being a multicore fiber having two cores with a small diameter running adjacent to each other and surrounded by a common cladding so that an appreciable amount of cross-coupling occurs therein;
- said means for measuring the alterations in the parameters measuring the changes in the light passing through each of the cores in response to deformation of the fiber, said means for measuring including means for directing each of the beams coupled from the two cores separately at separate light-receiving surfaces with each of the light-receiving surfaces being a light-sensitive surface of a light-sensitive detector;
one end of the fiber being provided with a mirror so that all light is coupled into and out of the fiber at the opposite end; and
said means for coupling including a light source, a beam divider mirror disposed in the path of the beam from said light source and the paths of the two beams emitted from the cores, and lens means for focusing the light reflected by the beam divider mirror into the ends of each of the cores.
- said means for measuring the alterations in the parameters measuring the changes in the light passing through each of the cores in response to deformation of the fiber, said means for measuring including means for directing each of the beams coupled from the two cores separately at separate light-receiving surfaces with each of the light-receiving surfaces being a light-sensitive surface of a light-sensitive detector;
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16. In a sensing device having a sensing element including an optical fiber, means for coupling light into the fiber and means for measuring alterations in specific physical parameters of the light passing through the fiber to determine special physical influences applied to the fiber, the improvements comprising the fiber being a multicore fiber having at least two adjacently extending cores surrounded by a common cladding and said means for measuring the alterations in the parameters measuring the changes in the light passing through each of the cores in response to deformation of the fiber, said means for measuring including means for conducting the light emitted from each of the cores along a separate path for at least a part of the distance, said means for conducting including a controllable optical phase modulator arranged in one of said separate paths to enable modulating the light in said one path.
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17. In a sensing device having a sensing element including an optical fiber, means for coupling light into the fiber and means for measuring alterations in specific physical parameters of the light passing through the fiber to determine special physical influences applied to the fiber, the improvements comprising the fiber being a multicore fiber having a pair of adjacently extending cores surrounded by a common cladding, each of the cores of the pair being spaced apart in the fiber a sufficient amount so that no appreciable cross-coupling occurs therebetween;
- and said means for measuring the alterations in the parameters measuring the changes in the light passing through each of the cores in response to deformation of the fiber, said means for measuring including an optical directional coupler having a pair of input gates and a pair of output gates, said input gates receiving light emitted from the pair of cores and said output gates emitting two beams of superimposed light, said means for measuring including a light-receiving surface arranged in each of the superimposed beams to observe the amount of interference therein.
Specification