US3874782A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light-guiding switch, modulator and deflector employing antisotropic substrate
Assignee: AT&T Inc
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Filing: 1973-10-01
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Granted: 1975-04-01
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Expires: 1993-10-01
Abstract
Abstract There is disclosed a light beam switching, modulating and deflecting device which is comprised of a thin dielectric film or strip waveguide deposited on an anisotropic (i.e., uniaxial) crystalline substrate. The guide and substrate parameters are selected so that one polarization of an optical wave is supported as a guided mode in the guide and the other, orthogonal polarization is not supported. Applied electric field components or acoustic strain components interact with the substrate to cause a coupling of the guided wave from the supported polarization to the unsupported polarization. The wave, upon being coupled to the unsupported polarization, is automatically and immediately radiated out of a guided mode into a freely propagating substrate mode. The unique principle of operation of the device, involving a combination of polarization discrimination in the guide and polarization coupling through an electro-optic or acousto-optic modulation of the substrate, eliminates the need for phase-matching. Noncritical, spatially uniform electric field or acoustic strain components applied to the substrate can thus provide the desired effect. The structure and operation of the device are thus generally simpler than those of similar prior art alternatives.
Inventors
- 👤 Ronald Vernon Schmidt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 13:42
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/03; G02F1/035; G02F1/011; G02F1/11; G02F1/125
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
236 words
An optical device of the type comprising a transparent substrate having first and second substantially flat, opposing major surfaces, a body of transparent material disposed on the first major surface of said substrate having a thickness so as to be capable of guiding a wave of optical electromagnetic radiation within that dimension, and means for launching a wave of optical electromagnetic radiation into a guided mode in said body to propagate substantially parallel to the first major surface of said substrate, said device being characterized in that said substrate is formed of an anisotropic crystalline material having an optic axis, a first index of refraction for a wave with electric vector polarized parallel to the optic axis and a second index of refraction for a wave with electric vector polarized normal to the optic axis, the thickness and refractive index of said waveguiding body and the orientation of the optic axis of said substrate with respect to the first major surface being selected so that said body supports as a guided wave one polarization of said wave but not the other, orthogonal polarization of said wave, said device being further characterized by means for interacting with said anisotropic substrate to couple at least a portion of said guided wave from the supported polarization to the unsupported polarization in said waveguiding body, said coupled portion of said wave propagating immediately out of said body into said substrate.
Claim 2
Dependent Claim
236 words
An optical device of the type comprising a transparent substrate having first and second substantially flat, opposing major surfaces, a body of transparent material disposed on the first major surface of said substrate having a thickness so as to be capable of guiding a wave of optical electromagnetic radiation within that dimension, and means for launching a wave of optical electromagnetic radiation into a guided mode in said body to propagate substantially parallel to the first major surface of said substrate, said device being characterized in that said substrate is formed of an anisotropic crystalline material having an optic axis, a first index of refraction for a wave with electric vector polarized parallel to the optic axis and a second index of refraction for a wave with electric vector polarized normal to the optic axis, the thickness and refractive index of said waveguiding body and the orientation of the optic axis of said substrate with respect to the first major surface being selected so that said body supports as a guided wave one polarization of said wave but not the other, orthogonal polarization of said wave, said device being further characterized by means for interacting with said anisotropic substrate to couple at least a portion of said guided wave from the supported polarization to the unsupported polarization in said waveguiding body, said coupled portion of said wave propagating immediately out of said body into said substrate.
Claim 3
Dependent Claim
29 words
The device of claim 1 in which said anisotropic substrate is a uniaxial crystal having a single optic axis oriented parallel to the first major surface of said substrate.
Claim 4
Dependent Claim
29 words
The device of claim 1 in which said anisotropic substrate is a uniaxial crystal having a single optic axis oriented normal to the first major surface of said substrate.
Claim 5
Dependent Claim
16 words
The device of claim 2 in which said anisotropic substrate consists essentially of lithium niobate (LiNbO3).
Claim 6
Dependent Claim
14 words
The device of claim 3 in which said anisotropic substrate consists essentially of quartz.
Claim 7
Dependent Claim
58 words
The device of claim 1 in which the refractive index of said waveguiding body exceeds both the first refractive index and the second refractive index of said substrate and the thickness of said waveguiding body is sufficiently thin so that said body supports as a guided wave one polarization but not the other, orthogonal polarization of said wave.
Claim 8
Dependent Claim
33 words
The device of claim 1 in which the refractive index of said waveguiding body has a value between the first refractive index of said substrate and the second refractive index of said substrate.
Claim 9
Dependent Claim
121 words
The device of claim 1 in which said waveguiding body is a film disposed on substantially the entire area of the first major surface of said substrate and in which said substrate interacting means comprises a pair of elongated strip electrodes, one of which is formed on said film, the other of which is formed on the second major surface of said substrate, said electrodes having tHeir longest dimension essentially parallel to the direction of propagation of the guided wave in said film, and a source means for applying a voltage between said electrodes to introduce a spatially uniform electric field component in said substrate which causes the coupling of the guided wave from the supported polarization to the unsupported polarization.
Claim 10
Dependent Claim
101 words
The device of claim 1 in which said waveguiding body is a strip having a width of the order of its thickness, said strip being disposed on the first major surface of said substrate and in which said substrate interacting means comprises a pair of elongated strip electrodes disposed on the first major surface of said substrate on opposite sides of said strip, and a source means for applying a voltage between said electrodes to introduce a spatially uniform electric field component in said substrate which causes the coupling of the guided wave from the supported polarization to the unsupported polarization.
Claim 11
Dependent Claim
101 words
The device of claim 1 in which said substrate interacting means comprises means for launching an acoustic surface wave propagating in said substrate essentially antiparallel to the direction of propagation of the guided wave in said waveguiding body to introduce in said substrate acoustic strain components which cause the polarization coupling of the guided wave, said acoustic wave launching means providing an acoustic surface wave of variable wavelength, the coupled portion of said wave propagating out of said body into said substrate at an angle with respect to the first major surface substantially directly related to the acoustic surface wave wavelength.
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) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |