US4239337A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magneto-optic modulator using dielectric mirrors
Assignee: AT&T Inc
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Filing: 1979-06-08
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Granted: 1980-12-16
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Expires: 1999-06-08
Abstract
Abstract A magneto-optic modulator of the bounce-cavity type is disclosed wherein the mirrors that are attached to the garnet crystal to provide the reflections are multilayered dielectric mirrors. By polarizing the input beam such that its E vector is perpendicular to the plane of incidence substantially total reflection is achieved from the mirrors and all of the input beam emerges from the garnet crystal. A metal film deposited on a plane of the crystal that is perpendicular to the mirrors permits the establishment of a magnetic field that is substantially parallel to the reflected beams within the crystal. When the field is established by passing current through the film, much of the light is lost during each of the reflections since substantial amounts of the polarized light having polarizations in the plane of incidence are coupled through the dielectric mirrors. Hence the intensity of the output beam is modulated by the current in the metal film.
Inventors
- 👤 Joe C. Campbell
- 👤 Kam-Yin Lau
- 👤 Julian Stone
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:16
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/09
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
67 words
A magneto-optic modulator for modulating the intensity of an input light beam comprising, a magneto-optic material and two mirrors mounted in parallel planes with the magneto-optic material between the mirrors so as to establish a cavity in the material in which multiple reflections of the input beam from the mirrors can be confined, characterized in that, at least one of said mirrors is a multilayered dielectric mirror.
Claim 2
Dependent Claim
67 words
A magneto-optic modulator for modulating the intensity of an input light beam comprising, a magneto-optic material and two mirrors mounted in parallel planes with the magneto-optic material between the mirrors so as to establish a cavity in the material in which multiple reflections of the input beam from the mirrors can be confined, characterized in that, at least one of said mirrors is a multilayered dielectric mirror.
Claim 3
Dependent Claim
16 words
A magneto-optic modulator as defined in claim 1 wherein said magneto-optic material is a garnet crystal.
Claim 4
Dependent Claim
18 words
A magneto-optic modulator as defined in claim 2 wherein said garnet crystal includes the materials yttrium and iron.
Claim 5
Dependent Claim
34 words
A magneto-optic modulator as defined in claim 2 wherein said modulator further includes a metal film deposited on a plane of said crystal that is substantially perpendicular to the parallel planes of said mirrors.
Claim 6
Dependent Claim
22 words
A magneto-optic modulator as defined in claim 4 wherein said metal film is separated from said garnet crystal by an insulating layer.
Claim 7
Dependent Claim
97 words
A bounce-cavity magneto-optic modulator for amplitude modulation of the intensity of a linearly polarized input light beam in response to an input signal comprising, a magneto-optic medium having opposite parallel surfaces, reflecting means mounted on each of said parallel surfaces of said medium for reflecting said input light beam in a zig-zag path in said medium, and magnetic field means responsive to said input signal for changing the magnetic field in said medium so as to change the polarization of said input light beam, characterized in that said reflecting means includes at least one multilayered dielectric mirror.
Claim 8
Dependent Claim
97 words
A bounce-cavity magneto-optic modulator for amplitude modulation of the intensity of a linearly polarized input light beam in response to an input signal comprising, a magneto-optic medium having opposite parallel surfaces, reflecting means mounted on each of said parallel surfaces of said medium for reflecting said input light beam in a zig-zag path in said medium, and magnetic field means responsive to said input signal for changing the magnetic field in said medium so as to change the polarization of said input light beam, characterized in that said reflecting means includes at least one multilayered dielectric mirror.
Claim 9
Dependent Claim
16 words
A magneto-optic modulator as defined in claim 6 wherein said magneto-optic medium is a garnet crystal.
Claim 10
Dependent Claim
18 words
A magneto-optic modulator as defined in claim 7 wherein said garnet crystal includes the materials yttrium and iron.
Claim 11
Dependent Claim
31 words
A magneto-optic modulator as defined in claim 7 wherein said magnetic field means is a metal film deposited on said crystal on a surface that is perpendicular to said parallel surfaces.
Claim 12
Dependent Claim
22 words
A magneto-optic modulator as defined in claim 9 wherein said metal film is separated from said garnet crystal by an insulating layer.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-12-16 | 1984-06-16 | 1984-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-16 | 1988-06-16 | 1988-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-16 | 1992-06-16 | 1992-12-16 | $7700.00 | Window Closed / Lapsed |