US4926177A
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Optical analog-digital converter provided with a nonlinear optical element and an optical feedback system for the output lights of said element
Assignee: Canon Inc
•
Filing: 1988-05-19
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Granted: 1990-05-15
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Expires: 2008-05-19
Abstract
Abstract An optical analog-digital converter comprises a nonlinear optical element having a threshold value for the intensity of an input light and producing a first and a second output light from the input light with the threshold value as a reference. The optical element produces a first output light of intensity corresponding to a digital signal meaning the digital 0 and a second output light of intensity proportional to the input light intensity when the intensity of the input light is smaller than the threshold value, and produces a first output light of an intensity corresponding to a digital signal meaning the digit 1 and a second output light of intensity equal to the input light intensity minus the threshold value when the intensity of the input light is greater than the threshold value. A device inputs to the nonlinear optical element a light having an intensity distribution corresponding to an analog signal, an optical feedback system causes the second output light of the nonlinear optical element produced from the input light to be again input to the nonlinear optical element, and a device provided in the feedback system amplifiers the second output light.
Inventors
- 👤 Hajime Sakata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 00:30
CPC Classifications
G; G02; G02F; G02F7/00
Claims Analysis
Total Claims: 71
Claim 1
Independent Claim
192 words
An optical analog-digital converter comprising: a nonlinear optical element having a threshold value for the intensity of an input light and producing a first and a second output light from said input light with said threshold value as a reference, said element producing a first output light of intensity corresponding to a digital signal meaning the digit 0 and a second output light of intensity proportional to the input light intensity when the intensity of said input light is smaller than said threshold value, and producing a first output light of intensity corresponding to a digital signal meaning the digit 1 and a second output light of intensity equal to the input light intensity minus the threshold value when the intensity of said input light is greater than said threshold value; means for inputting to said nonlinear optical element a light having an intensity distribution corresponding to an analog signal; an optical feedback system for causing the second output light of said nonlinear optical element produced from said input light to be again input to said nonlinear optical element; and means provided in said feedback system for amplifying said second output light.
Claim 2
Dependent Claim
192 words
An optical analog-digital converter comprising: a nonlinear optical element having a threshold value for the intensity of an input light and producing a first and a second output light from said input light with said threshold value as a reference, said element producing a first output light of intensity corresponding to a digital signal meaning the digit 0 and a second output light of intensity proportional to the input light intensity when the intensity of said input light is smaller than said threshold value, and producing a first output light of intensity corresponding to a digital signal meaning the digit 1 and a second output light of intensity equal to the input light intensity minus the threshold value when the intensity of said input light is greater than said threshold value; means for inputting to said nonlinear optical element a light having an intensity distribution corresponding to an analog signal; an optical feedback system for causing the second output light of said nonlinear optical element produced from said input light to be again input to said nonlinear optical element; and means provided in said feedback system for amplifying said second output light.
Claim 3
Dependent Claim
19 words
An optical analog-digital converter according to claim 1, further comprising an optical delay device provided in said feedback system.
Claim 4
Dependent Claim
49 words
An optical analog-digital converter according to claim 2, wherein said optical delay device comprises two optical storage devices series-connected in said feedback system, and a clock device for supplying to said optical storage devices a clock signal indicative of the timing of the input and output of a light.
Claim 5
Dependent Claim
42 words
An optical analog-digital converter according to claim 2, wherein said optical delay device comprises an optical fiber from one end of which said second output light enters and from the other end of which such light emerges toward said nonlinear optical element.
Claim 6
Dependent Claim
18 words
An optical analog-digital converter according to claim 1, wherein said amplifying means amplifies said second output light twice.
Claim 7
Dependent Claim
16 words
An optical analog-digital converter according to claim 1, wherein said amplifying means comprises an amplifying laser.
Claim 8
Dependent Claim
18 words
An optical analog-digital converter according to claim 1, wherein said nonlinear optical element comprises a nonlinear Fabry-Perot resonator.
Claim 9
Dependent Claim
64 words
An optical analog-digital converter according to claim 7, wherein said resonator satisfies the following condition: R.sub.B e.sup.-2αd -0.15≦R.sub.F ≦R.sub.B e.sup.-2αd +0.15, where R F is the intensity reflectance of the incidence side resonating surface, R B is the intensity reflectance of the transmission side resonating surface, α is the absorption rate of the nonlinear medium in the resonator, and d is the resonator length.
Claim 10
Dependent Claim
18 words
An optical analog-digital converter according to claim 1, wherein said analog signal is indicative of two-dimensional image information.
Claim 11
Dependent Claim
24 words
An optical analog-digital converter according to claim 9, wherein said input means comprises an input image and a light source for illuminating said image.
Claim 12
Dependent Claim
191 words
An optical analog-digital converter comprising: a nonlinear optical element having a threshold value for the intensity of an input light and producing a first and a second output light from said input light with said threshold value as a reference, said element producing a first output light of intensity corresponding to a digital signal meaning the digit 0 and a second output light of intensity proportional to the input light intensity when the intensity of said input light is smaller than said threshold value, and producing a first output light of intensity corresponding to a digital signal meaning the digit 1 and a second output light of intensity equal to the input light intensity minus the threshold value when the intensity of said input light is greater than said threshold value; means for inputting to said nonlinear optical element a light having an intensity distribution corresponding to an analog signal; an optical feedback system for causing the second output light of said nonlinear optical element produced from said input light to be again input to said nonlinear optical element; and means for controlling the threshold value of said nonlinear optical element.
Claim 13
Dependent Claim
191 words
An optical analog-digital converter comprising: a nonlinear optical element having a threshold value for the intensity of an input light and producing a first and a second output light from said input light with said threshold value as a reference, said element producing a first output light of intensity corresponding to a digital signal meaning the digit 0 and a second output light of intensity proportional to the input light intensity when the intensity of said input light is smaller than said threshold value, and producing a first output light of intensity corresponding to a digital signal meaning the digit 1 and a second output light of intensity equal to the input light intensity minus the threshold value when the intensity of said input light is greater than said threshold value; means for inputting to said nonlinear optical element a light having an intensity distribution corresponding to an analog signal; an optical feedback system for causing the second output light of said nonlinear optical element produced from said input light to be again input to said nonlinear optical element; and means for controlling the threshold value of said nonlinear optical element.
Claim 14
Dependent Claim
19 words
An optical analog-digital converter according to claim 11, further comprising an optical delay device provided in said feedback system.
Claim 15
Dependent Claim
49 words
An optical analog-digital converter according to claim 12, wherein said optical delay device comprises two optical storage devices series-connected in said feedback system, and a clock device for supplying to said optical storage devices a clock signal indicative of the timing of the input and output of a light.
Claim 16
Dependent Claim
42 words
An optical analog-digital converter according to claim 12, wherein said optical delay device comprises an optical fiber from one end of which said second output light enters and from the other end of which such light emerges toward said nonlinear optical element.
Claim 17
Dependent Claim
26 words
An optical analog-digital converter according to claim 11, wherein said control means comprises a light source for inputting a bias light to said nonlinear optical element.
Claim 18
Dependent Claim
37 words
An optical analog-digital converter according to claim 11, wherein said control means reduces the threshold value of said nonlinear optical element to 1/2 of that during the input each time said second output light is fed back.
Claim 19
Dependent Claim
18 words
An optical analog-digital converter according to claim 11, wherein said nonlinear optical element comprises a nonlinear Fabry-Perot resonator.
Claim 20
Dependent Claim
64 words
An optical analog-digital converter according to claim 17, wherein said resonator satisfies the following condition: R.sub.B e.sup.-2αd -0.15≦R.sub.F ≦R.sub.B e.sup.-2αd +0.15, where R F is the intensity reflectance of the incidence side resonating surface, R B is the intensity reflectance of the transmission side resonating surface, α is the absorption rate of the nonlinear medium in the resonator, and d is the resonator length.
Claim 21
Dependent Claim
18 words
An optical analog-digital converter according to claim 11, wherein said analog signal is indicative of two-dimensional image information.
Claim 22
Dependent Claim
24 words
An optical analog-digital converter according to claim 19, wherein said input means comprises an input image and a light source for illuminating said image.
Claim 23
Dependent Claim
179 words
An optical analog-digital converter comprising: a nonlinear optical element having a threshold value for the intensity of an input light and producing a first and a second output light from said input light with said threshold value as a reference, said element producing a first output light of intensity corresponding to a digital signal meaning the digit 0 and a second output light of intensity proportional to the input light intensity when the intensity of said input light is smaller than said threshold value, and producing a first output light of intensity corresponding to a digital signal meaning the digit 1 and a second output light of intensity equal to the input light intensity minus the threshold value when the intensity of said input light is greater than said threshold value; means for inputting to said nonlinear optical element a light having an intensity distribution corresponding to an analog signal; means for outputting the first output light of said nonlinear optical element produced from said input light; and means for controlling the threshold value of said nonlinear optical element.
Claim 24
Dependent Claim
179 words
An optical analog-digital converter comprising: a nonlinear optical element having a threshold value for the intensity of an input light and producing a first and a second output light from said input light with said threshold value as a reference, said element producing a first output light of intensity corresponding to a digital signal meaning the digit 0 and a second output light of intensity proportional to the input light intensity when the intensity of said input light is smaller than said threshold value, and producing a first output light of intensity corresponding to a digital signal meaning the digit 1 and a second output light of intensity equal to the input light intensity minus the threshold value when the intensity of said input light is greater than said threshold value; means for inputting to said nonlinear optical element a light having an intensity distribution corresponding to an analog signal; means for outputting the first output light of said nonlinear optical element produced from said input light; and means for controlling the threshold value of said nonlinear optical element.
Claim 25
Dependent Claim
26 words
An optical analog-digital converter according to claim 21, wherein said control means comprises a light source for inputting a bias light to said nonlinear optical element.
Claim 26
Dependent Claim
19 words
An optical analog digital converter according to claim 21, wherein said nonlinear optical element comprises a nonlinear Fabry-Perot resonator.
Claim 27
Dependent Claim
64 words
An optical analog-digital converter according to claim 23, wherein said resonator satisfies the following condition: R.sub.B e.sup.-2αd -0.15≦R.sub.F ≦R.sub.B e.sup.-2αd +0.15, where R F is the intensity reflectance of the incidence side resonating surface, R B is the intensity reflectance of the transmission side resonating surface, α is the absorption rate of the nonlinear medium in the resonator, and d is the resonator length.
Claim 28
Dependent Claim
19 words
An optical analog-digital converter according to claim 21, wherein said analog signal is indicative of two dimensional image information.
Claim 29
Dependent Claim
24 words
An optical analog-digital converter according to claim 25, wherein said input means comprises an input image and a light source for illuminating said image.
Claim 30
Dependent Claim
201 words
An optical analog-digital converter for converting an analog signal into a digital signal of plural bits, comprising: a plurality of nonlinear optical elements successively provided correspondingly to said bits, each of said elements having a threshold value for the intensity of an input light and producing a first output light of intensity corresponding to a digital signal meaning the digit 0 and a second output light of intensity proportional to the input light intensity when the intensity of the input light is smaller than said threshold value, and producing a first output light of intensity corresponding to a digital signal meaning the digit 1 and a second output light of intensity equal to the input light intensity minus the threshold value when the intensity of the input light is greater than said threshold value; means for inputting to the nonlinear optical element corresponding to the first bit a light having an intensity distribution corresponding to an analog signal; means for inputting the second output light of the nonlinear optical element corresponding to the preceding bit to the nonlinear optical element corresponding to the next bit; and means for outputting a plurality of first output lights produced by said nonlinear optical elements.
Claim 31
Dependent Claim
201 words
An optical analog-digital converter for converting an analog signal into a digital signal of plural bits, comprising: a plurality of nonlinear optical elements successively provided correspondingly to said bits, each of said elements having a threshold value for the intensity of an input light and producing a first output light of intensity corresponding to a digital signal meaning the digit 0 and a second output light of intensity proportional to the input light intensity when the intensity of the input light is smaller than said threshold value, and producing a first output light of intensity corresponding to a digital signal meaning the digit 1 and a second output light of intensity equal to the input light intensity minus the threshold value when the intensity of the input light is greater than said threshold value; means for inputting to the nonlinear optical element corresponding to the first bit a light having an intensity distribution corresponding to an analog signal; means for inputting the second output light of the nonlinear optical element corresponding to the preceding bit to the nonlinear optical element corresponding to the next bit; and means for outputting a plurality of first output lights produced by said nonlinear optical elements.
Claim 32
Dependent Claim
23 words
An optical analog-digital converter according to claim 27, further comprising means for controlling the threshold value of each of said nonlinear optical elements.
Claim 33
Dependent Claim
28 words
An optical analog-digital converter according to claim 28, wherein said control means comprises a light source for inputting a bias light to each of said nonlinear optical elements.
Claim 34
Dependent Claim
24 words
An optical analog digital converter according to claim 27, further comprising optical amplifier means provided in the optical path between said nonlinear optical elements.
Claim 35
Dependent Claim
18 words
An optical analog-digital converter according to claim 30, wherein said amplifier means amplifies said second output light twice.
Claim 36
Dependent Claim
16 words
An optical analog-digital converter according to claim 30, wherein said amplifier means comprises an amplifying laser.
Claim 37
Dependent Claim
43 words
An optical analog-digital converter according to claim 27, wherein the threshold value of each of said nonlinear optical element is set to 1/2 of the threshold value of the nonlinear optical element corresponding to the bit preceding the bit indicated by that element.
Claim 38
Dependent Claim
20 words
An optical analog-digital converter according to claim 27, wherein each of said nonlinear optical elements comprises a nonlinear Fabry-Perot resonator.
Claim 39
Dependent Claim
64 words
An optical analog-digital converter according to claim 34, wherein said resonator satisfies the following condition: R.sub.B e.sup.-2αd -0.15≦R.sub.F ≦R.sub.B e.sup.-2αd +0.15, where R F is the intensity reflectance of the incidence side resonating surface, R B is the intensity reflectance of the transmission side resonating surface, α is the absorption rate of the nonlinear medium in the resonator, and d is the resonator length.
Claim 40
Dependent Claim
18 words
An optical analog-digital converter according to claim 27, wherein said analog signal is indicative of two-dimensional image information.
Claim 41
Dependent Claim
24 words
An optical analog-digital converter according to claim 36, wherein said input means comprises an input image and a light source for illuminating said image.
Claim 42
Dependent Claim
89 words
An optical analog-digital converter comprising: a nonlinear Fabry-Perot resonator satisfying the following condition: R.sub.B e.sup.-2αd -0.15≦R.sub.F ≦R.sub.B e.sup.-2αd +0.15, where R F is the intensity reflectance of the incidence side resonating surface, R B is the intensity reflectance of the transmission side resonating surface, α is the absorption rate of the nonlinear medium in the resonator, and d is the resonator length; means for inputting to said resonator a light having an intensity distribution corresponding to an analog signal; and means for outputting the transmitted light of said resonator.
Claim 43
Dependent Claim
89 words
An optical analog-digital converter comprising: a nonlinear Fabry-Perot resonator satisfying the following condition: R.sub.B e.sup.-2αd -0.15≦R.sub.F ≦R.sub.B e.sup.-2αd +0.15, where R F is the intensity reflectance of the incidence side resonating surface, R B is the intensity reflectance of the transmission side resonating surface, α is the absorption rate of the nonlinear medium in the resonator, and d is the resonator length; means for inputting to said resonator a light having an intensity distribution corresponding to an analog signal; and means for outputting the transmitted light of said resonator.
Claim 44
Dependent Claim
18 words
An optical analog-digital converter according to claim 38, wherein said analog signal is indicative of two-dimensional image information.
Claim 45
Dependent Claim
24 words
An optical analog-digital converter according to claim 39, wherein said input means comprises an input image and a light source for illuminating said image.
Claim 46
Dependent Claim
166 words
An optical analog digital converter for a polychromatic light indicating different signals depending on the wavelength, comprising: means for dividing said polychromatic light into a plurality of lights of different wavelengths; a plurality of nonlinear optical elements to which said plurality of lights are input, each of said elements having a threshold value for the intensity of an input light and producing a first output light of intensity corresponding to a digital signal meaning the digit 0 and a second output light of intensity proportional to the input light intensity when the intensity of said input light is smaller than said threshold value, and producing a first output light of intensity corresponding to a digital signal meaning the digit 1 and a second output light of intensity equal to the input light intensity minus the threshold value when the intensity of said input light is greater than said threshold value; and means for outputting the plurality of first output lights produced by said nonlinear optical elements.
Claim 47
Dependent Claim
166 words
An optical analog digital converter for a polychromatic light indicating different signals depending on the wavelength, comprising: means for dividing said polychromatic light into a plurality of lights of different wavelengths; a plurality of nonlinear optical elements to which said plurality of lights are input, each of said elements having a threshold value for the intensity of an input light and producing a first output light of intensity corresponding to a digital signal meaning the digit 0 and a second output light of intensity proportional to the input light intensity when the intensity of said input light is smaller than said threshold value, and producing a first output light of intensity corresponding to a digital signal meaning the digit 1 and a second output light of intensity equal to the input light intensity minus the threshold value when the intensity of said input light is greater than said threshold value; and means for outputting the plurality of first output lights produced by said nonlinear optical elements.
Claim 48
Dependent Claim
17 words
An optical analog-digital converter according to claim 41, wherein said dividing means comprises a color resolving prism.
Claim 49
Dependent Claim
34 words
An optical analog-digital converter according to claim 41, further comprising an optical feedback system for causing the second output lights of said nonlinear optical elements to be again input to said nonlinear optical elements.
Claim 50
Dependent Claim
19 words
An optical analog-digital converter according to claim 43, further comprising an optical delay device provided in said feedback system.
Claim 51
Dependent Claim
48 words
An optical analog-digital converter according to claim 44, wherein said optical device comprises two optical storage devices series-connected in said feedback system, and a clock device for supplying to said optical storage devices a clock signal indicative of the timing of the input and output of a light.
Claim 52
Dependent Claim
42 words
An optical analog-digital converter according to claim 44, wherein said optical delay device comprises an optical fiber from one end of which said second output light enters and from the other end of which said light emerges toward said nonlinear optical elements.
Claim 53
Dependent Claim
23 words
An optical analog-digital converter according to claim 42, further comprising means for controlling the threshold value of each of said nonlinear optical elements.
Claim 54
Dependent Claim
26 words
An optical analog-digital converter according to claim 47, wherein said control means comprises a light source for inputting a bias light to said nonlinear optical elements.
Claim 55
Dependent Claim
39 words
An optical analog-digital converter according to claim 47, wherein said control means reduces the threshold value of each of said nonlinear optical elements to 1/2 of that during the input each time said second output lights are fed back.
Claim 56
Dependent Claim
20 words
An optical analog-digital converter according to claim 41, wherein each of said nonlinear optical elements comprises a nonlinear Fabry-Perot resonator.
Claim 57
Dependent Claim
64 words
An optical analog-digital converter according to claim 50, wherein said resonator satisfies the following condition: R.sub.B e.sup.-2αd -0.15≦R.sub.F ≦R.sub.B e.sup.-2αd +0.15, where R F is the intensity reflectance of the incidence side resonating surface, R B is the intensity reflectance of the transmission side resonating surface, α is the absorption rate of the nonlinear medium in the resonator, and d is the resonator length.
Claim 58
Dependent Claim
19 words
An optical analog-digital converter according to claim 41, wherein said polychromatic light is indicative of two-dimensional color image information.
Claim 59
Dependent Claim
26 words
An optical analog-digital converter according to claim 52, wherein said input means comprises an input color image and a white light source for illuminating said image.
Claim 60
Dependent Claim
166 words
An optical analog-digital converter for effecting analog-digital conversion of a color image, comprising: means for time-serially separating and extracting from said color image lights indicative of image information of different colors; a nonlinear optical element to which said extracted lights are time-serially input; said element having a threshold value for the intensity of an input light and producing a first output light of intensity corresponding to a digital signal meaning the digit 0 and a second output light of intensity proportional to the input light intensity when the intensity of the input light is smaller than said threshold value, and producing a first output light of intensity corresponding to a digital signal meaning the digit 1 and a second output light of intensity equal to the input light intensity minus the threshold value when the intensity of the input light is greater than said threshold value; and means for time-serially outputting first output lights corresponding to the different color signals produced by said nonlinear optical elements.
Claim 61
Dependent Claim
166 words
An optical analog-digital converter for effecting analog-digital conversion of a color image, comprising: means for time-serially separating and extracting from said color image lights indicative of image information of different colors; a nonlinear optical element to which said extracted lights are time-serially input; said element having a threshold value for the intensity of an input light and producing a first output light of intensity corresponding to a digital signal meaning the digit 0 and a second output light of intensity proportional to the input light intensity when the intensity of the input light is smaller than said threshold value, and producing a first output light of intensity corresponding to a digital signal meaning the digit 1 and a second output light of intensity equal to the input light intensity minus the threshold value when the intensity of the input light is greater than said threshold value; and means for time-serially outputting first output lights corresponding to the different color signals produced by said nonlinear optical elements.
Claim 62
Dependent Claim
32 words
An optical analog-digital converter according to claim 54, wherein said extracting means comprises a plurality of light sources for illuminating said color image with lights of different wavelengths and turned on time-serially.
Claim 63
Dependent Claim
34 words
An optical analog-digital converter according to claim 54, further comprising an optical feedback system for causing the second output light of said nonlinear optical element to be again input to said nonlinear optical element.
Claim 64
Dependent Claim
19 words
An optical analog-digital converter according to claim 56, further comprising an optical delay device provided in said feedback system.
Claim 65
Dependent Claim
49 words
An optical analog-digital converter according to claim 57, wherein said optical delay device comprises two optical storage devices series-connected in said feedback system, and a clock device for supplying to said optical storage devices a clock signal indicative of the timing of the input and output of a light.
Claim 66
Dependent Claim
42 words
An optical analog-digital converter according to claim 57, wherein said optical delay device comprises an optical fiber from one end of which said second output light enters and from the other end of which said light emerges toward said nonlinear optical element.
Claim 67
Dependent Claim
21 words
An optical analog-digital converter according to claim 54, further comprising means for controlling the threshold value of said nonlinear optical element.
Claim 68
Dependent Claim
26 words
An optical analog-digital converter according to claim 60, wherein said control means comprises a light source for inputting a bias light to said nonlinear optical element.
Claim 69
Dependent Claim
37 words
An optical analog-digital converter according to claim 60, wherein said control means reduces the threshold value of said nonlinear optical element to 1/2 of that during the input each time said second output light is fed back.
Claim 70
Dependent Claim
18 words
An optical analog-digital converter according to claim 54, wherein said nonlinear optical element comprises a nonlinear Fabry-Perot resonator.
Claim 71
Dependent Claim
64 words
An optical analog-digital converter according to claim 63, wherein said resonator satisfies the following condition: R.sub.B e.sup.-2αd -0.15≦R.sub.F ≦R.sub.B e.sup.-2αd +0.15, where R F is the intensity reflectance of the incidence side resonating surface, R B is the intensity reflectance of the transmission side resonating surface, α is the absorption rate of the nonlinear medium in the resonator, and d is the resonator length.
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