Patent UST870005I4 successfully refreshed from Google Patents.
US4730171A
Expired / Lapsed
US
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Optical signal modulators
Assignee: Nortel Networks Ltd
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Filing: 1986-04-28
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Granted: 1988-03-08
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Expires: 2006-04-28
Abstract
Abstract An optical fiber having a core and a cladding has its cladding interrupted and an electro-optic crystal disposed at the interruption, a modulating electric field being applied via electrodes to the crystal to control its refractive index and thereby modulate an optical signal carried by the fiber. In one embodiment the interruption in the cladding extends all around the core. In another embodiment the fiber is embedded in a curved position in epoxy material, and the epoxy material and fiber are ground down on the outside of the curve to interrupt the cladding and expose the core, the electro-optic crystal being provided on the ground surface. A second fiber can be inverted on the crystal to provide an optical coupler. The electro-optic crystal is for example a single crystal of a tetragonal phosphate.
Inventors
- 👤 Vincent C. So
- 👤 Paul J. Vella
- 👤 Richard P. Hughes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 21:02
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/29; G02F1/31; G02F1/313; G02F1/3131; G02F1/01; G02F1/011; G02F1/0115
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
70 words
An optical signal modulator comprising: an optical fiber, comprising a core and a cladding, for carrying an optical signal to be modulated; an interruption in said cladding, the core being continuous at said interruption; an electro-optic crystal of a tetragonal phosphate material disposed at said interruption; and means for applying a modulating electric field to the electro-optic crystal to vary the refractive index thereof, thereby to modulate the optical signal.
Claim 2
Dependent Claim
70 words
An optical signal modulator comprising: an optical fiber, comprising a core and a cladding, for carrying an optical signal to be modulated; an interruption in said cladding, the core being continuous at said interruption; an electro-optic crystal of a tetragonal phosphate material disposed at said interruption; and means for applying a modulating electric field to the electro-optic crystal to vary the refractive index thereof, thereby to modulate the optical signal.
Claim 3
Dependent Claim
29 words
A modulator as claimed in claim 1 wherein the means for applying a modulating electric field to the electro-optic crystal comprises a plurality of spaced electrodes on the crystal.
Claim 4
Dependent Claim
28 words
A modulator as claimed in claim 1 wherein the interruption in the cladding extends substantially all around the optical fiber core along a portion of the length thereof.
Claim 5
Dependent Claim
52 words
A modulator as claimed in claim 3 wherein the electro-optic crystal comprises a plurality of electro-optic crystal members disposed substantially all around the optical fiber core at the interruption in the cladding, and the means for applying a modulating electric field comprises a plurality of spaced electrodes on each electro-optic crystal member.
Claim 6
Dependent Claim
20 words
A modulator as claimed in claim 4 wherein each electro-optic crystal member comprises a single crystal of a tetragonal phosphate.
Claim 7
Dependent Claim
35 words
A modulator as claimed in claim 1 and comprising means for holding a portion of the optical fiber in a curved position, wherein the interruption in the cladding is on the outside of the curve.
Claim 8
Dependent Claim
37 words
A modulator as claimed in claim 6 wherein the interruption in the cladding comprises a substantially flat surface formed on the optical fiber on the outside of said curve and extending to the core of the fiber.
Claim 9
Dependent Claim
26 words
A modulator as claimed in claim 7 wherein the electro-optic crystal has a substantially flat surface abutting the substantially flat surface formed on the optical fiber.
Claim 10
Dependent Claim
23 words
A modulator as claimed in claim 6 wherein the holding means comprises material in which said portion of the optical fiber is embedded.
Claim 11
Dependent Claim
41 words
A modulator as claimed in claim 8 wherein the means for applying a modulating electric field comprises a plurality of spaced electrodes and the holding means comprises material in which said portion of the optical fiber and said electrodes are embedded.
Claim 12
Dependent Claim
14 words
A modulator as claimed in claim 9 wherein the holding means comprises epoxy material.
References Cited (Backward Citations)
US3208342A
Cited
US3312827A
Cited
US3770339A
Cited
US3923373A
Cited
US4392712A
Cited
US4185884A
Cited
US4474431A
Cited
US4386822A
Cited
US4387954A
Cited
JPS5810701A
Cited
US4461536A
Cited
JPS59148030A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-03-08 | 1991-09-07 | 1992-03-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-08 | 1995-09-07 | 1996-03-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-08 | 1999-09-07 | 2000-03-08 | $7700.00 | Window Closed / Lapsed |