US5317666A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Waveguide nonlinear optical frequency converter with integral modulation and optimization means
Assignee: Eastman Kodak Co
•
Filing: 1992-09-29
•
Granted: 1994-05-31
•
Expires: 2012-09-29
Abstract
Abstract An optical, waveguide, quasi-phase-matching frequency converter has integral means to vary the efficiency of the quasi-phase-matching frequency conversion process resulting in intensity modulation of the device output; said frequency converter has integral means to optimize the quasi-phase-matching frequency conversion process resulting in optimum device output; and said frequency converter has integral input signal polarization mode conversion means in optional combination with the conversion optimization means for modulating the optimized device output. Methods for modulating and optimizing the quasi-phase-matching frequency converted signal by electro-optically controlling the dispersion of the frequency converting medium are also disclosed.
Inventors
- 👤 John A. Agostinelli
- 👤 Jose M. Mir
- 👤 Joseph F. Revelli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:52
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/35; G02F1/37; G02F1/377; G02F1/3775; G02F1/353; G02F1/3544; G02F1/3546
Claims Analysis
Total Claims: 43
Claim 1
Independent Claim
143 words
A method for converting the frequency ω on of an input signal to create an output signal having frequency ω out and modulating the intensity of the output signal, comprising the steps of: (a) applying the input signal to a waveguide including a variable dispersion, nonlinear active region of length L having a periodically poled grating of period X for quasi-phase-matching; b) quasi-phase-matching the input signal and the output signal; c) varying the dispersion of the active region to maintain a coherence length between the input and output signals equal to (n/2)X, where n equals an odd integer; and d) one of discretely and continuously changing the dispersion from a value for optimum frequency conversion by an amount equal to plus or minus mλ/2L where m is an integer and λ is the free space wavelength, to produce less than optimum frequency conversion.
Claim 2
Independent Claim
143 words
A method for converting the frequency ω on of an input signal to create an output signal having frequency ω out and modulating the intensity of the output signal, comprising the steps of: (a) applying the input signal to a waveguide including a variable dispersion, nonlinear active region of length L having a periodically poled grating of period X for quasi-phase-matching; b) quasi-phase-matching the input signal and the output signal; c) varying the dispersion of the active region to maintain a coherence length between the input and output signals equal to (n/2)X, where n equals an odd integer; and d) one of discretely and continuously changing the dispersion from a value for optimum frequency conversion by an amount equal to plus or minus mλ/2L where m is an integer and λ is the free space wavelength, to produce less than optimum frequency conversion.
Claim 3
Dependent Claim
29 words
The method of claim 1 in which the step of varying the dispersion of the active region comprises the step of applying an electric field across the active region.
Claim 4
Independent Claim
99 words
A method for converting the frequency ω in of an input signal to create an output signal having frequency ω out and modulating the intensity of the output signal, comprising the steps of: (a) inputting the input signal into a waveguide including a nonlinear active region having a length L and a periodically poled grafting of period X, in which the input signal has one of a TM and a TE polarization state; (b) switching the polarization state of the input signal between the TE and TM polarization states; and (c) quasi-phase-matching the input signal and the output signal.
Claim 5
Independent Claim
99 words
A method for converting the frequency ω in of an input signal to create an output signal having frequency ω out and modulating the intensity of the output signal, comprising the steps of: (a) inputting the input signal into a waveguide including a nonlinear active region having a length L and a periodically poled grafting of period X, in which the input signal has one of a TM and a TE polarization state; (b) switching the polarization state of the input signal between the TE and TM polarization states; and (c) quasi-phase-matching the input signal and the output signal.
Claim 6
Dependent Claim
48 words
The method of claim 3 in which the step of switching the polarization of the input signal between the TE and TM polarization states comprises the step of applying an electric field to a portion of the waveguide anterior to the active region to create an electro-optic effect.
Claim 7
Independent Claim
123 words
A method for converting the frequency ω in of an input signal to create an output signal having frequency ω out and optimizing the efficiency of the frequency change, comprising the steps of: (a) inputting the input signal into a waveguide including a variable dispersion, nonlinear active region having a length L and a periodically poles grating of period X; b) varying the dispersion of the active region to maintain a coherence length between the input and output signals equal to the value (n/2)X, where n equals an odd integer; c) quasi-phase-matching the input signal and the output signal; and (d) monitoring the power of the output signal while electro-optically varying the dispersion of the active region to maintain optimum output signal power.
Claim 8
Independent Claim
123 words
A method for converting the frequency ω in of an input signal to create an output signal having frequency ω out and optimizing the efficiency of the frequency change, comprising the steps of: (a) inputting the input signal into a waveguide including a variable dispersion, nonlinear active region having a length L and a periodically poles grating of period X; b) varying the dispersion of the active region to maintain a coherence length between the input and output signals equal to the value (n/2)X, where n equals an odd integer; c) quasi-phase-matching the input signal and the output signal; and (d) monitoring the power of the output signal while electro-optically varying the dispersion of the active region to maintain optimum output signal power.
Claim 9
Dependent Claim
21 words
The method of claim 5 wherein varying the dispersion comprises the step of applying an electric field across the active region.
Claim 10
Independent Claim
128 words
A method for converting the frequency ω in of a polarized input signal to create an output signal having frequency ω out and modulating the intensity of the output signal, comprising the steps of: (a) inputting the input signal into a waveguide including a variable dispersion, nonlinear active region having a length L and a periodically poled grating of period X; (b) alternating the polarization state of the input signal between one of a TE and TM polarization state prior to propagating the signal through the active region; (c) quasi-phase-matching the input signal and the output signal; and (d) changing the dispersion of the active region to maintain a coherence length between the input and output signals equal to one-half of the grating period of the active region.
Claim 11
Independent Claim
128 words
A method for converting the frequency ω in of a polarized input signal to create an output signal having frequency ω out and modulating the intensity of the output signal, comprising the steps of: (a) inputting the input signal into a waveguide including a variable dispersion, nonlinear active region having a length L and a periodically poled grating of period X; (b) alternating the polarization state of the input signal between one of a TE and TM polarization state prior to propagating the signal through the active region; (c) quasi-phase-matching the input signal and the output signal; and (d) changing the dispersion of the active region to maintain a coherence length between the input and output signals equal to one-half of the grating period of the active region.
Claim 12
Dependent Claim
44 words
The method of claim 1 or 2 wherein the step of applying an electric field across the active region comprises the step of creating an electric field over every other half-period of the active region wherein said half-period regions have constant ferroelectric polarization directions.
Claim 13
Independent Claim
103 words
A method for converting the frequency ω in of an input signal to create an output signal having frequency ω out and modulating the intensity of the output signal, comprising the steps of: (a) inputting the input signal into a waveguide including a variable dispersion, nonlinear active region having a length L and a periodically poled grating of period X for quasi-phase-matching, in which the input signal has one of a TM and a TE polarization state; (b) switching the polarization state of the input signal between the TE and TM polarization states; and (c) quasi-phase-matching the input signal and the output signal.
Claim 14
Independent Claim
103 words
A method for converting the frequency ω in of an input signal to create an output signal having frequency ω out and modulating the intensity of the output signal, comprising the steps of: (a) inputting the input signal into a waveguide including a variable dispersion, nonlinear active region having a length L and a periodically poled grating of period X for quasi-phase-matching, in which the input signal has one of a TM and a TE polarization state; (b) switching the polarization state of the input signal between the TE and TM polarization states; and (c) quasi-phase-matching the input signal and the output signal.
Claim 15
Dependent Claim
21 words
The method of either of claim 1, 3, 5 or 7 wherein the input and output signals are optical frequency signals.
Claim 16
Dependent Claim
29 words
The method of claim 7 in which the step of changing the dispersion of the active region comprises the step of applying an electric field across the active region.
Claim 17
Dependent Claim
88 words
A quasi-phase-matching frequency converter for producing an intensity modulated output signal of frequency ω out from an input signal of frequency ω in , where ω in is different from ω out , comprising: (a) a waveguide including an active region of characteristic length L having quasi-phase-matching frequency conversion means and variable dispersion; and (b) integral modulation means further comprising means for varying the efficiency of quasi-phase-matched frequency conversion from the input signal of frequency ω in to the output signal of frequency ω out in the waveguide.
Claim 18
Dependent Claim
88 words
A quasi-phase-matching frequency converter for producing an intensity modulated output signal of frequency ω out from an input signal of frequency ω in , where ω in is different from ω out , comprising: (a) a waveguide including an active region of characteristic length L having quasi-phase-matching frequency conversion means and variable dispersion; and (b) integral modulation means further comprising means for varying the efficiency of quasi-phase-matched frequency conversion from the input signal of frequency ω in to the output signal of frequency ω out in the waveguide.
Claim 19
Dependent Claim
28 words
The frequency converter of claim 12 wherein the means for varying the efficiency of frequency conversion further comprises means for electro-optically controlling the dispersion of the active region.
Claim 20
Dependent Claim
76 words
A quasi-phase-matching frequency converter for producing an intensity modulated output signal of frequency ω out from an input signal of frequency ω in , where ω in is different from ω out , comprising: (a) a waveguide including an active region of characteristic length L having quasi-phase-matching frequency conversion means; and (b) integral modulation means further comprising means for selectively alternating the polarization mode of the input signal prior to propagating it through the active region.
Claim 21
Dependent Claim
76 words
A quasi-phase-matching frequency converter for producing an intensity modulated output signal of frequency ω out from an input signal of frequency ω in , where ω in is different from ω out , comprising: (a) a waveguide including an active region of characteristic length L having quasi-phase-matching frequency conversion means; and (b) integral modulation means further comprising means for selectively alternating the polarization mode of the input signal prior to propagating it through the active region.
Claim 22
Dependent Claim
35 words
The frequency converter of claim 14 wherein the means for alternating the polarization mode of the input signal further comprises means for alternating the polarization mode between one of a TE and TM polarization state.
Claim 23
Dependent Claim
96 words
A quasi-phase-matching frequency converter for optimizing the efficiency of quasi-phase-matched frequency conversion from an input signal of frequency ω in to an output signal of frequency ω out , where ω in is different from ω out comprising: (a) a waveguide including an active region of characteristic length L having quasi-phase-matching frequency conversion means and variable dispersion; and (b) integral means for electro-optically varying the dispersion of the active region; (c) detecting means opto-electronically responsive to the output signal for continuously measuring the output signal power, and feedback means for dynamically controlling the dispersion varying means.
Claim 24
Dependent Claim
96 words
A quasi-phase-matching frequency converter for optimizing the efficiency of quasi-phase-matched frequency conversion from an input signal of frequency ω in to an output signal of frequency ω out , where ω in is different from ω out comprising: (a) a waveguide including an active region of characteristic length L having quasi-phase-matching frequency conversion means and variable dispersion; and (b) integral means for electro-optically varying the dispersion of the active region; (c) detecting means opto-electronically responsive to the output signal for continuously measuring the output signal power, and feedback means for dynamically controlling the dispersion varying means.
Claim 25
Dependent Claim
42 words
The frequency converter of claim 16 further comprising in combination: (a) integral input signal polarization mode conversion means located ahead of the active region for selectively alternating the polarization mode of the input signal prior to propagating it through the active region.
Claim 26
Dependent Claim
35 words
The frequency converter of either claim 15 or claim 17 wherein alternating the polarization mode of the input signal further comprises means for applying an electric field across the waveguide anterior to the active region.
Claim 27
Dependent Claim
35 words
The frequency converter of either claim 13, 16 or 17 wherein means for electro-optically varying the dispersion of the active region further comprises means for creating an electric field in the active-region of the waveguide.
Claim 28
Dependent Claim
20 words
The device of either of claim 12, 16 or 17 wherein the quasi-phase-matching frequency conversion means comprise first-order said means.
Claim 29
Dependent Claim
23 words
The frequency converter of either of claim 12, 14, 16, or 17 wherein the input and output signal frequencies comprise optical signal frequencies.
Claim 30
Dependent Claim
59 words
The frequency converter of claim 19 wherein the means for creating an electric field in the active region of the waveguide comprises a pair of conducting electrodes in proximity to a portion of the waveguide, further comprising a top electrode in proximity to the active region and a bottom electrode in proximity to the bottom surface of the substrate.
Claim 31
Dependent Claim
10 words
The device of claim 22 wherein the electrodes are metal.
Claim 32
Dependent Claim
34 words
The frequency converter of claim 22 wherein the top electrode has a finger geometry for creating an electric field only in every other half-period region of the active region having a permanent ferroelectric polarization.
Claim 33
Dependent Claim
21 words
The frequency converter of claim 22 comprising at least one non-scattering, non-absorbing buffer layer interposed between each electrode and the waveguide.
Claim 34
Dependent Claim
18 words
The device of either claim 12, 14, 16 or 17 wherein the waveguide comprises a nonlinear optical waveguide.
Claim 35
Dependent Claim
20 words
The device of claim 26 wherein the nonlinear optical waveguide comprises a surface modified, bulk inorganic crystalline, nonlinear optical material.
Claim 36
Dependent Claim
46 words
The device of claim 26 wherein the nonlinear optical waveguide comprises: (a) a substrate having an index of refraction n s ; and (b) an optical thin film having an index of refraction n f , supported by the substrate, wherein n f >n s .
Claim 37
Dependent Claim
31 words
The device of claim 28 wherein the thin film material comprises a non-scattering, non-absorbing inorganic, nonlinear, noncentrosymmetric, ferroelectric, crystalline material and further wherein the substrate comprises a non-scattering, non-absorbing monocrystalline structure.
Claim 38
Dependent Claim
15 words
The device of claim 28 wherein the optical thin film material comprises an organic material.
Claim 39
Dependent Claim
76 words
The device of claim 29 wherein the thin film material comprises a material selected from a group of materials consisting of LiTaO 3 , LiNbO 3 , LiNb x Ta 1-x O 3 (0<x<1), KNbO 3 , KTa x Nb 1-x O 3 (0<x≦0.7), β-BaB 2 O 4 , Ba 2 NaNb 5 O 15 , KTiOPO 4 , KTiOAsO 4 , BaTiO 3 , LiIO 3 , ZnO and PLZT compositions having permanent ferroelectric polarizations.
Claim 40
Dependent Claim
56 words
The device of claim 29 wherein the substrate comprises a material selected from a group of materials consisting of sapphire (monocrystalline Al 2 O 3 ), MgO, LiF, Y:ZrO 2 , Ca:ZrO 2 , LiTaO 3 , SrTiO 3 , LaAlO 3 , LaGaO 3 , NdGaO 3 , quartz, and MgAl 2 O 4 .
Claim 41
Dependent Claim
40 words
The device of claim 28 wherein the optical waveguide comprises a thin film/substrate combination selected from a group of combinations consisting of LiTaO 3 /sapphire, LiNbO 3 /sapphire, LiTaO 3 /MgO, LiNbO 3 /MgO and LiNbO 3 /LiTaO 3 .
Claim 42
Dependent Claim
12 words
The device of claim 26 wherein the waveguide comprises a channel waveguide.
Claim 43
Dependent Claim
19 words
The method of either claim 1, 3, 4, 7 or 9 wherein the quasi-phase-matching frequency conversion comprises first-order quasi-phase-matching.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-05-30 | 1997-11-29 | 1998-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-05-30 | 2001-11-29 | 2002-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-05-30 | 2005-11-29 | 2006-05-31 | $7700.00 | Window Closed / Lapsed |