US4818064A — Sensor array and method of selective interferomet…

Claim 1

Independent Claim 146 words

A sensor array for monitoring environmental effects on a selected sensor, comprising: a plurality of interferometers, with at least one interferometer incorporating a sensor segment which influences light traveling therein in response to selected environmental effects, and with each interferometer defining a particular optical path length difference; means for providing to said interferometers an optical signal comprising a plurality of component signals at frequencies which are spaced from one another and at magnitudes such that said optical signal defines a waveform which reaches a maximum magnitude at a periodic rate which substantially corresponds to a difference in optical signal travel time through the optical paths of the interferometer which incorporates the selected sensor; and means for monitoring optical signals which have passed through at least one of said interferometers, to identify the environmental influence which affected the optical signal which passed through the selected optical sensor.

Claim 2

Dependent Claim 146 words

A sensor array for monitoring environmental effects on a selected sensor, comprising: a plurality of interferometers, with at least one interferometer incorporating a sensor segment which influences light traveling therein in response to selected environmental effects, and with each interferometer defining a particular optical path length difference; means for providing to said interferometers an optical signal comprising a plurality of component signals at frequencies which are spaced from one another and at magnitudes such that said optical signal defines a waveform which reaches a maximum magnitude at a periodic rate which substantially corresponds to a difference in optical signal travel time through the optical paths of the interferometer which incorporates the selected sensor; and means for monitoring optical signals which have passed through at least one of said interferometers, to identify the environmental influence which affected the optical signal which passed through the selected optical sensor.

Claim 3

Dependent Claim 40 words

A sensor array as defined in claim 1 wherein the waveform reaches a minimum magnitude at times defining intervals which substantially correspond with differences in optical signal travel time through the optical paths of other interferometers in the sensor array.

Claim 4

Dependent Claim 45 words

A sensor array as defined in claim 1, further comprising means for modifying characteristics of the component signals to change said optical signal waveform so that said periodic rate corresponds to a difference in optical signal travel time through another interferometer which incorporates another sensor.

Claim 5

Dependent Claim 19 words

A sensor array as defined in claim 3 wherein the means for modifying characteristics comprises an optical phase modulator.

Claim 6

Dependent Claim 18 words

A sensor array as defined in claim 3 wherein the means for modifying characteristics comprises a frequency modulator.

Claim 7

Dependent Claim 18 words

A sensor array as defined in claim 3 wherein the means for modifying characteristics comprises an amplitude modulator.

Claim 8

Dependent Claim 91 words

A sensor array as defined in claim 1 wherein the means for providing an optical signal comprises: a light source; a frequency synthesizer for producing a signal at a first selected frequency; an oscillator at a second selected frequency; means for mixing output of the oscillator and frequency synthesizer to produce a resultant signal comprised of frequencies including the second frequency plus the first frequency, and the second frequency minus the first frequency; and means for mixing light from the light source with the resultant signal to produce said optical signal.

Claim 9

Dependent Claim 35 words

A sensor array as defined in claim 7 wherein the resultant signal is an electrical signal and wherein the means for mixing light from the light source with the resultant signal comprises an acousto-optic cell.

Claim 10

Dependent Claim 43 words

A sensor array as defined in claim 1 wherein the means for monitoring comprises: a filter having an optical signal pass band which is narrower than the frequency band between said component signals; and means for analyzing optical signals received from the filter.

Claim 11

Independent Claim 163 words

An apparatus for remotely sensing environmental effects on a sensor, comprising: a source of optical illumination for providing an optical signal comprising a plurality of component signals at optical frequencies which are spaced from one another and of magnitudes such that said optical signal defines a periodic waveform having a maximum which recurs at a selected interval; a plurality of optical waveguides defining plural light paths for said optical signal, wherein at least a portion of a first one of said light paths comprises a sensing region which is sensitive to an environmental effect and which influences light propagating in the sensing region in response to said environmental effect, and wherein a path length difference between said first light path and a second one of said light paths produces a difference in optical signal travel time through said first and second light paths which substantially corresponds to said selected interval; and means for combining optical signals from said first and second light paths.

Claim 12

Independent Claim 163 words

An apparatus for remotely sensing environmental effects on a sensor, comprising: a source of optical illumination for providing an optical signal comprising a plurality of component signals at optical frequencies which are spaced from one another and of magnitudes such that said optical signal defines a periodic waveform having a maximum which recurs at a selected interval; a plurality of optical waveguides defining plural light paths for said optical signal, wherein at least a portion of a first one of said light paths comprises a sensing region which is sensitive to an environmental effect and which influences light propagating in the sensing region in response to said environmental effect, and wherein a path length difference between said first light path and a second one of said light paths produces a difference in optical signal travel time through said first and second light paths which substantially corresponds to said selected interval; and means for combining optical signals from said first and second light paths.

Claim 13

Dependent Claim 88 words

An apparatus as defined in claim 10 wherein the source of optical illumination comprises: a light source; a frequency synthesizer for producing a signal at a first selected frequency; an oscillator at a second selected frequency; means for mixing output of the oscillator and frequency synthesizer to produce a resultant signal comprised of frequencies including the second frequency plus the first frequency, and the second frequency minus the first frequency; and means for mixing light from the light source with the resultant signal to produce said optical signal.

Claim 14

Dependent Claim 34 words

An apparatus as defined in claim 11 wherein the resultant signal is an electrical signal and wherein the means for mixing light from the light source with the resultant signal comprises an acousto-optic cell.

Claim 15

Dependent Claim 45 words

An apparatus as defined in claim 10 wherein the waveform is at a substantially minimum magnitude at recurring intervals, so as to define periods between selected minimum magnitudes which substantially correspond with differences in optical signal travel time through other of said plural light paths.

Claim 16

Dependent Claim 34 words

An apparatus as defined in claim 10 wherein the source of optical illumination comprises: a light source; and means for acting on light from the light source to produce said plurality of component signals.

Claim 17

Dependent Claim 20 words

An apparatus as defined in claim 14 wherein the means for acting on light comprises an optical signal modulation device.

Claim 18

Dependent Claim 18 words

An apparatus as defined in claim 10 wherein the means for combining optical signals comprises an optical coupler.

Claim 19

Independent Claim 174 words

An apparatus for remotely sensing environmental effects on a sensor, comprising: a plurality of optical waveguides defining plural light paths, wherein at least a portion of a first of said light paths comprises a sensing region which is sensitive to an environmental effect and which influences light propagating in the sensing region in response to said environmental effect; means for providing an optical signal comprising a plurality of component signals at different frequencies for transmission to said plurality of optical waveguides; means for changing characteristics of the component signals such that the optical signal defines a periodic waveform having a maximum which recurs at a selected interval which substantially corresponds to difference in optical signal travel time through said first light path and optical signal travel time through a second of said light paths; and means for combining optical signals from the first and second light paths to provide an output signal comprising information representative of the environmental effect which influenced the portion of the optical signal which traveled through the first light path.

Claim 20

Independent Claim 174 words

An apparatus for remotely sensing environmental effects on a sensor, comprising: a plurality of optical waveguides defining plural light paths, wherein at least a portion of a first of said light paths comprises a sensing region which is sensitive to an environmental effect and which influences light propagating in the sensing region in response to said environmental effect; means for providing an optical signal comprising a plurality of component signals at different frequencies for transmission to said plurality of optical waveguides; means for changing characteristics of the component signals such that the optical signal defines a periodic waveform having a maximum which recurs at a selected interval which substantially corresponds to difference in optical signal travel time through said first light path and optical signal travel time through a second of said light paths; and means for combining optical signals from the first and second light paths to provide an output signal comprising information representative of the environmental effect which influenced the portion of the optical signal which traveled through the first light path.

Claim 21

Dependent Claim 24 words

An apparatus as defined in claim 17 wherein the means for providing an optical signal comprises: a light source; and an optical signal modulator.

Claim 22

Dependent Claim 21 words

An apparatus as defined in claim 17 wherein the means for changing characteristics of the component signals comprises a modulation device.

Claim 23

Dependent Claim 68 words

An apparatus as defined in claim 17 wherein the means for changing characteristics define a periodic waveform having minimums which occur at times such that intervals between various minimums substantially correspond with differences other than that between said first and second light paths, in optical signal travel time through the other plural light paths, thereby preventing coherent mixing of optical signals traveling in said other plural light paths.

Claim 24

Dependent Claim 18 words

An apparatus as defined in claim 20 wherein the means for changing characteristics comprises an optical signal modulator.

Claim 25

Independent Claim 151 words

An apparatus for remotely sensing environmental effects on a sensor, comprising: a plurality of optical interferometers, with at least one interferometer including a sensor segment which influences light traveling therein in response to environmental effects on the sensor segment, wherein each interferometer defines a particular optical path length difference; means for providing an optical signal for propagation to the plurality of optical interferometers, wherein said optical signal comprises a plurality of component signals which form a power spectrum defining an optical signal coherence function whose maximum magnitude repeats at a periodic rate which substantially corresponds to a difference in optical signal travel time through optical paths of a selected interferometer which includes a selected sensor segment; and means optically connected to the selected interferometer for providing an output signal comprising information representative of the environmental effect which influenced the portion of the optical signal which traveled through the selected sensor segment.

Claim 26

Independent Claim 151 words

An apparatus for remotely sensing environmental effects on a sensor, comprising: a plurality of optical interferometers, with at least one interferometer including a sensor segment which influences light traveling therein in response to environmental effects on the sensor segment, wherein each interferometer defines a particular optical path length difference; means for providing an optical signal for propagation to the plurality of optical interferometers, wherein said optical signal comprises a plurality of component signals which form a power spectrum defining an optical signal coherence function whose maximum magnitude repeats at a periodic rate which substantially corresponds to a difference in optical signal travel time through optical paths of a selected interferometer which includes a selected sensor segment; and means optically connected to the selected interferometer for providing an output signal comprising information representative of the environmental effect which influenced the portion of the optical signal which traveled through the selected sensor segment.

Claim 27

Dependent Claim 40 words

An apparatus as defined in claim 22 wherein the power spectrum also defines said coherence function as comprising minimum magnitudes with intervals between various minimum magnitudes substantially corresponding with differences in optical signal travel time through the non-selected optical interferometers.

Claim 28

Dependent Claim 49 words

An apparatus as defined in claim 22, further comprising means for modifying characteristics of the component signals to change the power spectrum so that said periodic rate corresponds to a difference in optical signal travel time through optical paths in another selected interferometer which includes another selected sensor segment.

Claim 29

Dependent Claim 18 words

An apparatus as defined in claim 24 wherein the means for modifying characteristics comprises an optical phase modulator.

Claim 30

Dependent Claim 17 words

An apparatus as defined in claim 24 wherein the means for modifying characteristics comprises a frequency modulator.

Claim 31

Dependent Claim 17 words

An apparatus as defined in claim 24 wherein the means for modifying characteristics comprises an amplitude modulator.

Claim 32

Dependent Claim 32 words

An apparatus as defined in claim 24 wherein the means for modifying characteristics comprise: a frequency synthesizer; and a mixer for mixing the output of the frequency synthesizer with the optical signal.

Claim 33

Dependent Claim 45 words

An apparatus as defined in claim 22, further comprising: a filter for receiving said output signal, said filter having an optical signal pass band which is narrower than the frequency band between said component signals; and means for analyzing optical signals received from the filter.

Claim 34

Independent Claim 210 words

An apparatus for remotely detecting environmental effects on a sensor, comprising: a plurality of optical interferometers, with at least one interferometer including a sensor segment which influences light traveling therein in response to environmental effects on the sensor segment, wherein each interferometer defines a particular optical path length difference; a light source for providing an optical signal; means for modulating the optical signal to form side bands of the optical signal, wherein said side bands form a power spectrum which defines a corresponding coherence function of the modulated optical signal; means for adjusting the side bands to modify the power spectrum so as to define a coherence function of the optical signal whose maximum magnitude repeats at a periodic rate which substantially corresponds to a difference in optical signal travel time through optical paths of a selected interferometer which includes a selected sensor segment, wherein the coherence function has minimums, and wherein time periods between various of said minimums substantially correspond to the difference in optical signal travel time through each of the non-selected interferometers; and means optically connected to the selected interferometer for providing an output signal comprising information representative of the environmental effect which influenced the portion of the optical signal which traveled through the selected sensor segment.

Claim 35

Independent Claim 210 words

An apparatus for remotely detecting environmental effects on a sensor, comprising: a plurality of optical interferometers, with at least one interferometer including a sensor segment which influences light traveling therein in response to environmental effects on the sensor segment, wherein each interferometer defines a particular optical path length difference; a light source for providing an optical signal; means for modulating the optical signal to form side bands of the optical signal, wherein said side bands form a power spectrum which defines a corresponding coherence function of the modulated optical signal; means for adjusting the side bands to modify the power spectrum so as to define a coherence function of the optical signal whose maximum magnitude repeats at a periodic rate which substantially corresponds to a difference in optical signal travel time through optical paths of a selected interferometer which includes a selected sensor segment, wherein the coherence function has minimums, and wherein time periods between various of said minimums substantially correspond to the difference in optical signal travel time through each of the non-selected interferometers; and means optically connected to the selected interferometer for providing an output signal comprising information representative of the environmental effect which influenced the portion of the optical signal which traveled through the selected sensor segment.

Claim 36

Dependent Claim 194 words

A sensor array for monitoring environmental effects on a selected sensor, comprising: a plurality of optical interferometers, with at least one interferometer including a sensor segment which influences light traveling therein in response to environmental effects on the sensor segment, wherein each interferometer includes separate optical paths which are combined at an output and each defines a particular optical path length difference; means for providing an optical signal so that portions of said optical signal pass through each of the plurality of optical interferometers, wherein said optical signal comprises a plurality of component signals which cooperate to define an optical signal waveform of a configuration such that coherent mixing of said portions of said optical signal occurs only at the output of a selected interferometer which includes a selected sensor segment, and only for those portions of said optical signal having passed through common optical paths prior to reaching the input of the selected interferometer and which pass through the separate optical paths of the selected interferometer, thereby providing an output signal comprising information representative of the environmental effect which influenced the portion of the optical signal which passed through the selected sensor segment.

Claim 37

Dependent Claim 194 words

A sensor array for monitoring environmental effects on a selected sensor, comprising: a plurality of optical interferometers, with at least one interferometer including a sensor segment which influences light traveling therein in response to environmental effects on the sensor segment, wherein each interferometer includes separate optical paths which are combined at an output and each defines a particular optical path length difference; means for providing an optical signal so that portions of said optical signal pass through each of the plurality of optical interferometers, wherein said optical signal comprises a plurality of component signals which cooperate to define an optical signal waveform of a configuration such that coherent mixing of said portions of said optical signal occurs only at the output of a selected interferometer which includes a selected sensor segment, and only for those portions of said optical signal having passed through common optical paths prior to reaching the input of the selected interferometer and which pass through the separate optical paths of the selected interferometer, thereby providing an output signal comprising information representative of the environmental effect which influenced the portion of the optical signal which passed through the selected sensor segment.

Claim 38

Dependent Claim 46 words

A sensor array as defined in claim 31 wherein the optical signal waveform has a maximum which repeats at a selected interval which substantially corresponds to a difference in optical signal travel time through optical paths of said selected interferometer which includes said selected sensor segment.

Claim 39

Dependent Claim 37 words

A sensor array as defined in claim 31 wherein the optical signal waveform is at a minimum at times defining intervals which substantially correspond with differences in optical signal travel time through optical paths of non-selected interferometers.

Claim 40

Independent Claim 218 words

An apparatus comprising: an interferometer arrangement comprising at least first, second, and third optical paths which form at least first and second interferometers, said first interferometer formed by one pair of said optical paths and said second interferometer formed by another pair of said optical paths, said one pair of optical paths defining a first path length difference and said another pair of said optical paths defining a second path length difference, said first path length difference being different from said second path length difference; and a source of optical illumination having first and second operational modes corresponding to said first and second path length differences, respectively, said first operational mode providing high coherence for light in said one pair of optical paths and low coherence for light in said another pair of optical paths, such that said light in said one pair of optical paths interferes and said light in said another pair of said optical paths is prevented from interfering, said second operational mode providing low coherence for said light in said one pair of optical paths and high coherence for said light in said another pair of optical paths, such that said light in said another pair of optical paths interferes and said light in said one pair of optical paths is prevented from interfering.

Claim 41

Independent Claim 218 words

An apparatus comprising: an interferometer arrangement comprising at least first, second, and third optical paths which form at least first and second interferometers, said first interferometer formed by one pair of said optical paths and said second interferometer formed by another pair of said optical paths, said one pair of optical paths defining a first path length difference and said another pair of said optical paths defining a second path length difference, said first path length difference being different from said second path length difference; and a source of optical illumination having first and second operational modes corresponding to said first and second path length differences, respectively, said first operational mode providing high coherence for light in said one pair of optical paths and low coherence for light in said another pair of optical paths, such that said light in said one pair of optical paths interferes and said light in said another pair of said optical paths is prevented from interfering, said second operational mode providing low coherence for said light in said one pair of optical paths and high coherence for said light in said another pair of optical paths, such that said light in said another pair of optical paths interferes and said light in said one pair of optical paths is prevented from interfering.

Claim 42

Dependent Claim 160 words

A sensor array for monitoring environmental effects on a selected sensor, comprising: a plurality of interferometers, with at least one interferometer incorporating a sensor segment which influences light traveling therein in response to selected environmental effects, and with each interferometer defining a particular optical path length difference; means for providing to said interferometers an optical signal comprising a plurality of component signals at frequencies which are spaced from one another and at magnitudes such that said optical signal defines a waveform which reaches a minimum magnitude at times defining intervals which substantially correspond to differences in optical signal travel time through the optical paths of those interferometers in the sensor array which are not selected to be monitored; and means for combining optical signals which have passed through a selected interferometer which incorporates a selected sensor segment, to provide an output signal comprising information representing the environmental effect which affected the optical signal which passed through the selected sensor segment.

Claim 43

Dependent Claim 160 words

A sensor array for monitoring environmental effects on a selected sensor, comprising: a plurality of interferometers, with at least one interferometer incorporating a sensor segment which influences light traveling therein in response to selected environmental effects, and with each interferometer defining a particular optical path length difference; means for providing to said interferometers an optical signal comprising a plurality of component signals at frequencies which are spaced from one another and at magnitudes such that said optical signal defines a waveform which reaches a minimum magnitude at times defining intervals which substantially correspond to differences in optical signal travel time through the optical paths of those interferometers in the sensor array which are not selected to be monitored; and means for combining optical signals which have passed through a selected interferometer which incorporates a selected sensor segment, to provide an output signal comprising information representing the environmental effect which affected the optical signal which passed through the selected sensor segment.

Claim 44

Dependent Claim 43 words

A sensor array as defined in claim 35 wherein the waveform reaches a maximum magnitude at a periodic rate which substantially corresponds to a difference in optical signal travel time through the optical paths of the selected interferometer which incorporates the selected sensor.

Claim 45

Independent Claim 179 words

A method for remotely sensing environmental effects on a sensor in a sensor array which includes a plurality of optical waveguides defining plural light paths, wherein at least a portion of a first of said light paths comprises a sensing region which is sensitive to an environmental effect and which influences light propagating in the sensing region in response to the environmental effect, the method comprising the steps of: providing to said plurality of optical waveguides an optical signal comprising a plurality of component signals at frequencies which are spaced from one another and of magnitudes such that said optical signal defines a periodic waveform having a maximum which recurs at a selected interval which substantially corresponds to difference in optical signal travel time through said first light path and optical signal travel time through a second of said light paths; and combining optical signals from the first and second light paths to provide an output signal comprising information representative of the environmental effect which influenced the portion of the optical signal which traveled through the first light path.

Claim 46

Independent Claim 179 words

A method for remotely sensing environmental effects on a sensor in a sensor array which includes a plurality of optical waveguides defining plural light paths, wherein at least a portion of a first of said light paths comprises a sensing region which is sensitive to an environmental effect and which influences light propagating in the sensing region in response to the environmental effect, the method comprising the steps of: providing to said plurality of optical waveguides an optical signal comprising a plurality of component signals at frequencies which are spaced from one another and of magnitudes such that said optical signal defines a periodic waveform having a maximum which recurs at a selected interval which substantially corresponds to difference in optical signal travel time through said first light path and optical signal travel time through a second of said light paths; and combining optical signals from the first and second light paths to provide an output signal comprising information representative of the environmental effect which influenced the portion of the optical signal which traveled through the first light path.

Claim 47

Dependent Claim 80 words

A method as defined in claim 37 wherein the step of providing an optical signal comprises the step of providing said signal wherein the plurality of component signals define said periodic waveform to additionally have minimums which occur at times such that intervals between various minimums substantially correspond with differences in optical signal travel time through other combinations of said plural light paths, thereby preventing coherent mixing of optical signals traveling in said other combinations of said plural light paths.

Claim 48

Dependent Claim 79 words

A method as defined in claim 37, further comprising the step of changing characteristics of the component signals to thereby change the optical signal waveform to define a maximum which recurs at a selected interval which substantially corresponds to difference in optical signal travel time through third and fourth of said light paths, while removing maximums which recur at an interval which substantially corresponds to the difference in optical signal travel time through said first and second light paths.

Claim 49

Independent Claim 147 words

A method for remotely sensing environmental effects on a sensor in a plurality of optical interferometers, with at least one interferometer including a sensor segment which influences light traveling therein in response to environmental effects on the sensor segment, wherein each interferometer defines a particular optical path length difference, the method comprising the steps of: providing an optical signal for propagation to the plurality of optical interferometers, wherein said optical signal comprises a plurality of component signals which form a power spectrum defining an optical signal coherence function whose maximum magnitude repeats at a periodic rate which substantially corresponds to a difference in optical signal travel time through optical paths of a selected interferometer which includes a selected sensor segment; and providing an output signal comprising information representative of the environmental effect which influenced the portion of the optical signal which traveled through the selected sensor segment.

Claim 50

Independent Claim 147 words

A method for remotely sensing environmental effects on a sensor in a plurality of optical interferometers, with at least one interferometer including a sensor segment which influences light traveling therein in response to environmental effects on the sensor segment, wherein each interferometer defines a particular optical path length difference, the method comprising the steps of: providing an optical signal for propagation to the plurality of optical interferometers, wherein said optical signal comprises a plurality of component signals which form a power spectrum defining an optical signal coherence function whose maximum magnitude repeats at a periodic rate which substantially corresponds to a difference in optical signal travel time through optical paths of a selected interferometer which includes a selected sensor segment; and providing an output signal comprising information representative of the environmental effect which influenced the portion of the optical signal which traveled through the selected sensor segment.

Claim 51

Dependent Claim 40 words

A method as defined in claim 40 wherein the power spectrum also defines said coherence function to comprise minimum magnitudes with intervals between various minimum magnitudes substantially corresponding with differences in optical signal travel time through the non-selected optical interferometers.

Claim 52

Dependent Claim 53 words

A method as defined in claim 40, further comprising the step of modifying characteristics of the component signals to change the power spectrum so that said periodic rate is changed to correspond to a difference in optical signal travel time through optical paths in another selected interferometer which includes another selected sensor segment.

Claim 53

Dependent Claim 43 words

A method as defined in claim 40, further comprising the step of monitoring a portion of the output signal which lies within a frequency bandwidth which is in the acoustic range and which is narrower than the frequency band between said component signals.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1992-04-03	1992-10-03	1993-04-04	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1996-04-03	1996-10-03	1997-04-04	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2000-04-03	2000-10-03	2001-04-04	$7700.00	Window Closed / Lapsed

Sensor array and method of selective interferometric sensing by use of coherence synthesis

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag