Sensor and method for detecting fiber optic faults
First Claim
1. A sensor for determining a length of an optical path, the sensor comprising:
- a light source configured to direct light along said optical path;
at least one modulator optically coupled to said light source, said at least one modulator configured to modulate at least a portion of said light as a function of a modulation signal;
a detector optically coupled to said at least one modulator configured to produce a detector output based upon a sensed intensity of said light at the end of said optical path; and
an electronics system configured to receive said detector output, and to provide an output indicative of the optical path length.
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Abstract
A fiber optic fault detector and generic fiber optic sensor system for detecting breaks in an optical fiber using a low coherence interferometric technique. The system comprises a light source configured to produce light traveling along the optical path, a modulator optically coupled to the light source configured to modulate at least a portion of the light as a function of a modulation signal, a detector optically coupled to the modulator configured to produce a detector output based upon a sensed intensity of the light, and an electronic array configured to receive the detector output and determine the optical fault. The low coherence interferometric technique allows for detection of a fault in the fiber with a minimal amount of test equipment and with higher measurement sensitivity and resolution. The system may alternatively include a transducer, positioned in place of the fiber under test, having a response which changes in reflective or optical path length. The system can be used in a LIDAR system, wherein telescope optics are used in place of the fiber under test, to transmit light and collect light scattered from objects or from the air.
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Citations
23 Claims
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1. A sensor for determining a length of an optical path, the sensor comprising:
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a light source configured to direct light along said optical path;
at least one modulator optically coupled to said light source, said at least one modulator configured to modulate at least a portion of said light as a function of a modulation signal;
a detector optically coupled to said at least one modulator configured to produce a detector output based upon a sensed intensity of said light at the end of said optical path; and
an electronics system configured to receive said detector output, and to provide an output indicative of the optical path length. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of determining a length of an optical path, the method comprising:
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generating a light along the optical path;
splitting said light into a first beam and a second beam;
modulating at least one of said first beam and said second beam in response to a modulation signal to induce a difference between said first beam and said second beam;
re-combining said first beam and said second beam to generate a recombined signal;
detecting an output intensity of said recombined signal at a detector;
adjusting said modulation signal as a function of said output intensity; and
computing said length of said optical path as a function of said modulation signal. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15)
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16. A system for determining the length of an optical fiber under test, the system comprising:
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a low coherence white light source configured to send light along an optical path defined by an optical fiber;
a phase modulator optically coupled to the light source for modulating at least a portion of the light in a first path relative to a second path;
a detector optically coupled to the optical path for producing a detector output based upon a length of the optical path; and
a processor for receiving the detector output, and for producing an output based upon the length of the optical path, wherein the light source has a coherence length shorter than a difference in path length between the first and the second paths. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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Specification