Patent US5039221A successfully refreshed from Google Patents.
US5039221A
Expired / Lapsed
US
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Interferometer calibration for fiber optic sensor arrays
Assignee: Northrop Grumman Guidance and Electronics Co Inc
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Filing: 1989-07-03
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Granted: 1991-08-13
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Expires: 2009-07-03
Abstract
Abstract A switch-selectable calibration signal is applied to an interferometric sensor channel of fiber optic sensor array for monitoring its operation. A calibration signal is applied at a single physical location to determine the channel scale factors and proper operability of multiple sensors at remote locations in the array. An optical signal input to each interferometric sensor channel in the array, and a compensating interferometer receives optical signals output from the fiber optic sensor array. A signal is applied to the compensating interferometer to form an output signal that simulates signals output from each interferometric sensor in the array. These signals are processed to determine the scale factor of each interferometer in the fiber optic sensor array.
Inventors
- 👤 Michael R. Layton
- 👤 James S. Bunn, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:31
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01D5/353; G01D5/35383
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
133 words
A system of calibrating the sensor channels of a fiber optic sensor array that includes at least one fiber optic interferometric sensor, comprising: means for providing an optical carrier signal input to the fiber optic sensor array such that a portion of the optical carrier signal is input to each interferometric sensor in the array; compensating interferometer means for receiving optical signals output from the fiber optic sensor array; means for applying a calibration signal having a selected amplitude to the compensating interferometer to form an output signal that simulates signals output from each interferometric sensor in the array; and means for processing signals output from the compensating interferometer to determine the amplitude of the portion of the carrier signal that is output from each interferometric sensor in the fiber optic sensor array.
Claim 2
Independent Claim
133 words
A system of calibrating the sensor channels of a fiber optic sensor array that includes at least one fiber optic interferometric sensor, comprising: means for providing an optical carrier signal input to the fiber optic sensor array such that a portion of the optical carrier signal is input to each interferometric sensor in the array; compensating interferometer means for receiving optical signals output from the fiber optic sensor array; means for applying a calibration signal having a selected amplitude to the compensating interferometer to form an output signal that simulates signals output from each interferometric sensor in the array; and means for processing signals output from the compensating interferometer to determine the amplitude of the portion of the carrier signal that is output from each interferometric sensor in the fiber optic sensor array.
Claim 3
Dependent Claim
48 words
The system of claim 1 wherein means for applying a signal to the compensating interferometer includes means for modulating the phase of light in the compensating interferometer to produce signals that are a superposition of the signals output from the fiber optic sensor array and a modulating signal.
Claim 4
Dependent Claim
57 words
The system of claim 2 wherein the means for providing an optical signal input to each interferometric sensor in the array comprises: a laser diode; means for generating a pulse signal; and means for modulating light output from the laser diode with the pulse signal to form a pulsed light wave that is a time-gated optical signal.
Claim 5
Dependent Claim
70 words
The system of claim 3, further comprising: means for synchronizing application of the phase modulation signal to the compensating interferometer with the arrival of signals from the interferometric sensors; means for demultiplexing signals output from the compensating interferometer to correlate pulses in the signals with the interferometric sensors so that the scale factor of each interferometric sensor may be determined; and means for demodulating the outputs from the demultiplexing means.
Claim 6
Dependent Claim
35 words
The system of claim 1 wherein the compensating interferometer includes a fiber optic Mach-Zehnder interferometer connected to the fiber optic sensor array to receive signals output from each of the interferometric sensors in the array.
Claim 7
Dependent Claim
51 words
The system of claim 5 wherein the means for applying a signal to the compensating interferometer includes phase modulating means for modulating the phase of light in the compensating interferometer to produce signals that are a superposition of the signals output from the fiber optic sensor array and a modulating signal.
Claim 8
Dependent Claim
35 words
The system of claim 1 wherein the compensating interferometer includes a fiber optic Michelson interferometer connected to the fiber optic sensor array to receive signals output from each of the interferometric sensors in the array.
Claim 9
Dependent Claim
51 words
The system of claim 7 wherein the means for applying a signal to the compensating interferometer includes phase modulating means for modulating the phase of light in the compensating inteferometer to produce signals that are a superposition of the signals output from the fiber optic sensor array and a modulating signal.
Claim 10
Dependent Claim
49 words
The system of claim 1 wherein means for applying a signal to the compensating interferometer includes means for shifting the frequency of light in the compensating interferometer to produce signals that are a superposition of the signals output from the fiber optic sensor array and a frequency modulating signal.
Claim 11
Dependent Claim
57 words
The system of claim 9 wherein the means for providing an optical signal input to each interferometric sensor in the array comprises: a laser diode; means for generating a pulse signal; and means for modulating light output from the laser diode with the pulse signal to form a pulsed light wave that is a time-gated optical signal.
Claim 12
Dependent Claim
70 words
The system of claim 10, further comprising: means for synchronizing application of the frequency modulating signal to the compensating interferometer with the arrival of signals from the interferometric sensors; means for demultiplexing signals output from the compensating interferometer to correlate pulses in the signals with the inteferometric sensors so that the scale factor of each interferometric sensor may be determined; and means for demodulating the outputs from the demultiplexing means.
Claim 13
Dependent Claim
34 words
The system of claim 11 wherein the compensating interferometer includes a fiber optic Mach-Zehnder interferometer connected to the fiber optic array to receive signals output from each of the interferometric sensors in the array.
Claim 14
Dependent Claim
35 words
The system of claim 11 wherein the compensating interferometer includes a fiber optic Michelson interferometer connected to the fiber optic sensor array to receive signals output from each of the interferometric sensors in the array.
Claim 15
Independent Claim
128 words
A method for calibrating the sensor channels of a fiber optic sensor array that includes at least one fiber optic interferometric sensor, comprising the steps of: providing an optical carrier signal input to the fiber optic sensor array such that a portion of the optical carrier signal is input to each interferometric sensor in the array; receiving optical signals output from the fiber optic sensor array with compensating interferometer means; applying a calbration signal to the compensating interferometer means to form an output signal that simulates signals output from each interferometric sensor in the array; and processing signals output from the compensating interferometer means to determine the amplitude of the portion of the carrier signal that is output from each interferometric sensor in the fiber optic sensor array.
Claim 16
Independent Claim
128 words
A method for calibrating the sensor channels of a fiber optic sensor array that includes at least one fiber optic interferometric sensor, comprising the steps of: providing an optical carrier signal input to the fiber optic sensor array such that a portion of the optical carrier signal is input to each interferometric sensor in the array; receiving optical signals output from the fiber optic sensor array with compensating interferometer means; applying a calbration signal to the compensating interferometer means to form an output signal that simulates signals output from each interferometric sensor in the array; and processing signals output from the compensating interferometer means to determine the amplitude of the portion of the carrier signal that is output from each interferometric sensor in the fiber optic sensor array.
Claim 17
Dependent Claim
52 words
The method of claim 14 wherein the step of applying a signal to the compensating interferometer means includes the step of modulating the phase of light in the compensating interferometer means to produce signals that are a superposition of the signals output from the fiber optic sensor array and a modulating signal.
Claim 18
Dependent Claim
57 words
The method of claim 15 wherein the step of providing an optical signal input to each interferometric sensor in the array comprises the steps of: providing a laser diode; generating a pulse signal; and modulating light output from the laser diode with the pulse signal to form a pulsed light wave that is a time-gated optical signal.
Claim 19
Dependent Claim
68 words
The method of claim 16, further comprising the steps of: sychronizing application of the phase modulation signal to the compensating interferometer means with the arrival of signals from the interferometric sensors; demultiplexing signals output from the compensating interferometer to correlate pulses in the signals with the interferometric sensors so that the scale factor of each interferometric sensor may be determined; and demodulating the outputs from the demultiplexing means.
Claim 20
Dependent Claim
41 words
The method of claim 14 including the step of forming the compensating interferometer means to include a fiber optic Mach-Zehnder interferometer connected to the fiber optic sensor array to receive signals output from each of the interferometric sensors in the array.
Claim 21
Dependent Claim
49 words
The method of claim 18 wherein the step of applying a signal to the compensating interferometer means includes modulating the phase of light in the compensating interferometer means to produce signals that are a superposition of the signals output from the fiber optic sensor array and a modulating signal.
Claim 22
Dependent Claim
41 words
The method of claim 14 including the step of forming the compensating interferometer means to include a fiber optic Michelson interferometer connected to the fiber optic sensor array to receive signals output from each of the interferometric sensors in the array.
Claim 23
Dependent Claim
48 words
The method claim 20 wherein the step of applying a signal to the compensating interferometer means includes modulating the phase of light in the compensating interferometer means to produce signals that are a superposition of the signals output from the fiber optic sensor array and a modulating signal.
Claim 24
Dependent Claim
49 words
The method of claim 14 wherein the step of applying a signal to the compensating interferometer means includes shifting the frequency of light in the compensating interferometer to produce signals that are a superposition of the signals output from the fiber optic sensor array and a frequency modulating signal.
Claim 25
Dependent Claim
54 words
The method of claim 22 wherein the step of providing an optical signal input to each interferometric sensor in the array comprises: providing a laser diode; generating a pulse signal; and modulating light output from the laser diode with the pulse signal to form a pulsed light wave that is a time-gated optical signal.
Claim 26
Dependent Claim
69 words
The method of claim 23, further comprising the steps of: synchronizing application of the frequency modulating signal to the compensating inteferometer means with the arrival of signals from the interferometric sensors; demultiplexing signals output from the compensating interferometer means to correlate pulses in the signals with the interferometric sensors so that the scale factor of each interferometric sensor may be determined; and demodulating the outputs from the demultiplexing means.
Claim 27
Dependent Claim
41 words
The method of claim 24 including the step of forming the compensating interferometer means to include a fiber optic Mach-Zehnder interferometer connected to the fiber optic sensor array to receive signals output from each of the interferometric sensors in the array.
Claim 28
Dependent Claim
41 words
The method of claim 24 including the step of forming the compensating interferometer means to include a fiber optic Michelson interferometer connected to the fiber optic sensors array to receive signals output from each of the interferometric sensors in the array.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-08-12 | 1995-02-11 | 1995-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-08-12 | 1999-02-11 | 1999-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-08-12 | 2003-02-11 | 2003-08-13 | $7700.00 | Window Closed / Lapsed |