US4582397A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Diospersive acousto-optic filter
Assignee: Oplink Communications LLC
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Filing: 1983-03-25
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Granted: 1986-04-15
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Expires: 2003-03-25
Abstract
Abstract An electronically tunable optical filter using acousto-optic interaction in a dispersive birefrigent crystal. The strong wavelength dispersion of birefringence in a class of uniaxial semiconductors near the band gap is utilized to enhance the spectral resolution of the tunable acousto-optic filter. The dispersive tunable acousto-optic filter provides a very large aperture while maintaining an extremely narrow bandwidth.
Inventors
- 👤 I-Cheng Chang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:18
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/11; G02F1/116
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
184 words
An acousto-optic apparatus for diffracting a portion of incident light from a first polarization to a second polarization within a passband of optical frequencies said apparatus comprising: a birefringent crystal, means for making a light beam incident on said crystal, said light beam passing through said crystal along a selected axis oriented at a nonzero angle with the optic axis of said crystal, means for exciting an acoustic wave in said crystal, the frequency of said acoustic wave being selected to define a center wavelength of said optical passband such that the sum of momentum vectors of said incident light and said acoustic wave are equal to the momentum vector of the diffracted light, means for changing said acoustic frequency to vary said center wavelength of said optical passband, and means for narrowing said optical passband by selecting said birefringent crystal such that the magnitude of ∂Δn/∂λ is at least five times as large as that of Δn/λ o , where Δn is the birefringence, λ o is the wavelength of incident light and ∂Δn/∂λ is the derivative of birefringence with respect to wavelength
Claim 2
Dependent Claim
184 words
An acousto-optic apparatus for diffracting a portion of incident light from a first polarization to a second polarization within a passband of optical frequencies said apparatus comprising: a birefringent crystal, means for making a light beam incident on said crystal, said light beam passing through said crystal along a selected axis oriented at a nonzero angle with the optic axis of said crystal, means for exciting an acoustic wave in said crystal, the frequency of said acoustic wave being selected to define a center wavelength of said optical passband such that the sum of momentum vectors of said incident light and said acoustic wave are equal to the momentum vector of the diffracted light, means for changing said acoustic frequency to vary said center wavelength of said optical passband, and means for narrowing said optical passband by selecting said birefringent crystal such that the magnitude of ∂Δn/∂λ is at least five times as large as that of Δn/λ o , where Δn is the birefringence, λ o is the wavelength of incident light and ∂Δn/∂λ is the derivative of birefringence with respect to wavelength
Claim 3
Dependent Claim
34 words
Apparatus of claim 1 including means for selecting the direction of the acoustic wave so that the tangents to the locus of the wavevectors for the incident light and diffracted light are substantially parallel.
Claim 4
Dependent Claim
11 words
Apparatus as in claim 1 wherein the said crystal comprises CdS.
Claim 5
Dependent Claim
13 words
Apparatus as in claim 1 wherein the said crystal comprises AgGaS 2 .
Claim 6
Dependent Claim
15 words
Apparatus as in claim 1 wherein the said crystal comprises CdGa 2 S 4 .
Claim 7
Dependent Claim
22 words
Apparatus as in claim 1 wherein the said crystal comprises CdS 1-x Se x compound where x ranges from 0 to 1.
Claim 8
Dependent Claim
23 words
Apparatus as in claim 1 wherein the said crystal comprises Zn x Cd 1-x S compound where x ranges from 0 to 1.
Claim 9
Dependent Claim
14 words
The apparatus of claim 2 wherein said apparatus comprises an electronically tunable optical filter.
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) | 1989-04-14 | 1989-10-14 | 1990-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-14 | 1993-10-14 | 1994-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-14 | 1997-10-14 | 1998-04-15 | $7700.00 | Window Closed / Lapsed |