Optical fiber interferosensor, signal-processing system for optical fiber interferosensor and recording medium
First Claim
1. A Fabry-Perot optical fiber interference sensor having a sensor part having opposed surfaces formed as parallel planes to each other in a measured clearance varied in response to physical quantities such as force, strain, pressure and temperature and the like, having a partial reflection mirror or an end surface of one optical fiber formed with a partial reflection mirror arranged in one surface side of said opposed surfaces, and having an end surface of the other optical fiber formed with a partial reflection mirror arranged in the other surface side of said opposed surfaces, in which a light of low coherence light source is guided to said the other optical fiber, either a reflected light or a transmission light modulated in wavelength in correspondence with a clearance size of said measured clearance through multiple reflection at said measured clearance is guided by the optical fiber, optical intensities in time-series corresponding to a clearance variation are attained by an optical intensity distribution sensor, either a minimum optical intensity position or a maximum optical intensity position is detected to attain said measured clearance and a value of said physical quantity is measured, wherein the same is comprised of;
- a wide range light source having a wide wavelength spectrum distribution acting as said low coherence light source;
an optical correlation signal extracting means for extracting a desired optical correlation signal from the output signal in time-series of said optical intensity distribution sensor; and
an extreme value position calculating means for attaining either a minimum position or a maximum position at said optical correlation signal in reference to the optical correlation signal outputted from said optical correlation signal extracting means.
2 Assignments
0 Petitions
Accused Products
Abstract
A low coherence light of wide range is fed into a Fabry-Perot load cell having a measured clearance varied in response to physical quantities such as force and pressure or the like to modulate its wavelength. The measured clearance is calculated by the variable gap Fabry-Perot interferometer and the signal processing part in the optical sensor and further the physical quantities are measured.
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Citations
17 Claims
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1. A Fabry-Perot optical fiber interference sensor having a sensor part having opposed surfaces formed as parallel planes to each other in a measured clearance varied in response to physical quantities such as force, strain, pressure and temperature and the like, having a partial reflection mirror or an end surface of one optical fiber formed with a partial reflection mirror arranged in one surface side of said opposed surfaces, and having an end surface of the other optical fiber formed with a partial reflection mirror arranged in the other surface side of said opposed surfaces, in which a light of low coherence light source is guided to said the other optical fiber, either a reflected light or a transmission light modulated in wavelength in correspondence with a clearance size of said measured clearance through multiple reflection at said measured clearance is guided by the optical fiber, optical intensities in time-series corresponding to a clearance variation are attained by an optical intensity distribution sensor, either a minimum optical intensity position or a maximum optical intensity position is detected to attain said measured clearance and a value of said physical quantity is measured, wherein the same is comprised of;
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a wide range light source having a wide wavelength spectrum distribution acting as said low coherence light source;
an optical correlation signal extracting means for extracting a desired optical correlation signal from the output signal in time-series of said optical intensity distribution sensor; and
an extreme value position calculating means for attaining either a minimum position or a maximum position at said optical correlation signal in reference to the optical correlation signal outputted from said optical correlation signal extracting means. - View Dependent Claims (3, 4, 5, 6, 7)
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2. A Fabry-Perot optical fiber interference sensor having a sensor part having opposed surfaces formed as parallel planes to each other in a measured clearance varied in response to physical quantities such as force, strain, pressure and temperature and the like, having a partial reflection mirror or an end surface of one optical fiber formed with a partial reflection mirror arranged in one surface side of said opposed surfaces, and having an end surface of the other optical fiber formed with a partial reflection mirror arranged in the other surface side of said opposed surfaces, in which a light of low coherence light source is guided to said the other optical fiber, either a reflected light or a transmission light modulated in wavelength correspondence with a clearance size of said measured clearance through multiple reflection at said measured clearance is guided by the optical fiber, optical intensities in time-series corresponding to a clearance variation are attained by an optical intensity distribution sensor, either a minimum optical intensity position or a maximum optical intensity position is detected to attain said measured clearance and a value of said physical quantity is measured, wherein the same is comprised of;
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a wide range light source having a wide wavelength spectrum distribution acting as said low coherence light source;
an optical correlation signal extracting means for extracting a desired optical correlation signal from the output signal in time-series of said optical intensity distribution sensor;
a high frequency component removing and processing means for removing a high frequency non-required component in the optical correlation signal outputted from said optical correlation signal extracting means; and
an extreme value position calculating means for attaining either a minimum position or a maximum position at said optical correlation signal in reference to the optical correlation signal having the high frequency non-required component removed which is outputted from said high frequency component removing and processing means. - View Dependent Claims (8)
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9. A signal processing system of a Fabry-Perot optical fiber interference sensor having a sensor part having opposed surfaces formed as parallel planes to each other in a measured clearance, having a partial reflection mirror or an end surface of one optical fiber formed with a partial reflection mirror arranged in one surface side of said opposed surfaces, and having an end surface of the other optical fiber formed with a partial reflection mirror arranged in the other surface side of said opposed surfaces, in which a light of low coherence light source is guided to said the other optical fiber, either a reflected light or a transmission light modulated in wavelength in correspondence with a clearance size of said measured clearance through multiple reflection at said measured clearance is guided by the optical fiber, optical intensities in time-series corresponding to a clearance variation are attained by an optical intensity distribution sensor, either a minimum optical intensity position or a maximum optical intensity position is attained to measure said measured clearance, wherein the same is comprised of;
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a wide range light source having a wide wavelength spectrum distribution acting as said low coherence light source;
an optical correlation signal extracting means for extracting a desired optical correlation signal from the output signal in time-series of said optical intensity distribution sensor; and
an extreme value position calculating means for attaining either a minimum position or a maximum position at said optical correlation signal in reference to the optical correlation signal outputted from said optical correlation signal extracting means.
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10. A signal processing system of a Fabry-Perot optical fiber interference sensor having a sensor part having opposed surfaces formed as parallel planes to each other in a measured clearance, having a partial reflection mirror or an end surface of one optical fiber formed with a partial reflection mirror arranged in one surface side of said opposed surfaces, and having an end surface of the other optical fiber formed with a partial reflection mirror arranged in the other surface side of said opposed surfaces, in which a light of low coherence light source is guided to said the other optical fiber, either a reflected light or a transmssion light modulated in wavelength in correspondence with a clearance size of said measured clearance through multiple reflection at said measured clearance is guided by the optical fiber, optical intensities in time-series corresponding to a clearance variation are attained by an optical intensity distribution sensor, either a minimum optical intensity position or a maximum optical intensity position is attained to measure said measured clearance, wherein the same is comprised of;
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a wide range light source having a wide wavelength spectrum distribution acting as said low coherence light source;
an optical correlation signal extracting means for extracting a desired optical correlation signal from the output signal in time-series of said optical intensity distribution sensor;
a high frequency component removing and processing means for removing a high frequency non-required component in the optical correlation signal outputted from said optical correlation signal extracting means; and
an extreme value position calculating means for attaining either a minimum position or a maximum position at said optical correlation signal in reference to the optical correlation signal outputted from said optical correlation signal extracting means and having high frequency non-required component removed.
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11. A Fabry-Perot optical fiber interference sensor having a sensor part having opposed surfaces formed as parallel planes to each other in a measured clearance varied in response to physical quantities such as force, strain, pressure and temperature and the like, having a partial reflection mirror or an end surface of one optical fiber formed with a partial reflection mirror arranged in one surface side of said opposed surfaces, and having an end surface of the other optical fiber formed with a partial reflection mirror arranged in the other surface side of said opposed surfaces, in which a light of low coherence light source is guided to said the other optical fiber, any one of a reflected light and a transmission light modulated in wavelength in correspondence with a clearance size of said measured clearance through multiple reflection at said measured clearance is guided by the optical fiber, the light is condensed linearly in a uniform optical intensity distribution, radiated onto a linear image sensor through a Fizeau interferometer, a maximum optical intensity position at said linear image sensor is detected from an output of said linear image sensor to attain said measured clearance and a value of said physical quantity is measured, wherein the same is comprised of;
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an optical correlation signal extracting means for extracting a desired optical correlation signal from the output signal in time-series of said linear image sensor;
a non-required component removing and processing means for removing a high frequency non-required component and a low frequency non-required component of the output of said optical correlation signal extracting means;
a phase shift processing means for shifting by 90°
a phase of the output of said non-required component removing and processing means;
an envelope calculating means for attaining an envelope component of the output of said non-required component removing and processing means in reference to an output of said non-required component removing and processing means and an output of said phase shift processing means with its phase being shifted by 90°
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a peak position calculating means for differentiating an output of said envelope calculating means and attaining a zero-cross point where said differentiated value may cross with a level zero. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A signal processing system of a Fabry-Perot optical fiber interference sensor having a sensor part having opposed surfaces formed as parallel planes to each other in a measured clearance, having a partial reflection mirror or an end surface of one optical fiber formed with a partial reflection mirror arranged in one surface side of said opposed surfaces, and having an end surface of the other optical fiber formed with a partial reflection mirror arranged in the other surface side of said opposed surfaces, in which a light of low coherence light source is guided to said the other optical fiber, any one of a reflected light and a transmission light modulated in wavelength in correspondence with a clearance size of said measured clearance through multiple reflection at said measured clearance is guided by the optical fiber, the light is condensed in a linear manner under a uniform optical intensity distribution, radiated onto a linear image sensor through a Fizeau interferometer, the maximum optical intensity position at said linear image sensor is attained in reference to an output of said linear image sensor to measure said measured clearance, wherein the same is comprised of;
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an optical correlation signal extracting means for extracting a desired optical correlation signal from the output signal in time-series of said linear image sensor;
a non-required component removing and processing means for removing a high frequency non-required component and a low frequency non-required component of an output of said optical correlation signal extracting means;
a phase shift processing means for shifting by 90°
a phase of an output of said non-required component removing and processing means;
an envelope calculating means for attaining an envelope component of output of said non-required component removing and processing means in reference to an output of said non-required component removing and processing means and an output of said phase shift processing means with its phase being shifted by 90°
; and
a peak position calculating means for differentiating an output of said envelope calculating means to attain a zero-cross point where said differentiated value crosses with a level zero.
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Specification