Patent US3027470A successfully refreshed from Google Patents.
US3756690A
Expired / Lapsed
US
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Optical waveguide light modulator
Assignee: Corning Glass Works
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Filing: 1972-03-30
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Granted: 1973-09-04
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Expires: 1992-03-30
Abstract
Abstract Modulation of light in a fused silica optical waveguide is accomplished by a Faraday effect rotation of the plane of polarization of the light propagating in the waveguide. The fused silica waveguide utilized has unique characteristics of low attenuation and low depolarization due to the purity of the fused silica, the manner in which the fused silica is made, the use of the same base material for the core and cladding layer, and a single mode transmission characteristic. The low attenuation and low depolarization permit low strength magnetic fields to cause large rotations of the plane of polarization of the light beam in the waveguide. Because of the length of the light path exposed to the magnetic field, rotations of at least 90* can be accomplished with the application of as little as 100 oersteds of magnetic field along the longitudinal axis of the guide.
Inventors
- 👤 N Borrelli
- 👤 F Kapron
- 👤 D Keck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 19:38
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/09; G02F1/095
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
74 words
The optical modulator as recited in claim 1 and further including in combination therewith; means for polarizing light, said means being adjacent to said output face and oriented to pass only light from said output face having a polarization direction at an angle different from said initial predetermined direction, whereby light emanating from said output face passing through said means for polarizing is modulated in amplitude in accordance with modulation of said magnetic field.
Claim 2
Dependent Claim
25 words
The optical modulator as recited in claim 1 wherein said waveguide is folded with the folded sections having longitudinal axes parallel to said magnetic field.
Claim 3
Dependent Claim
15 words
The optical waveguide as recited in claim 3 wherein said waveguide is toroidal in form.
Claim 4
Dependent Claim
39 words
The optical modulator as recited in claim 1 wherein said core member and said cladding member are basically made of fused silica doped so that the index of refraction of said core member is greater than said cladding member.
Claim 5
Dependent Claim
37 words
The optical modulator as recited in claim 5 wherein said fused silica members are prepared in a flame hydrolysis process to obtain substantially pure fused silica, whereby said waveguide achieves exceptionally low attenuation and exceptionally low depolarization.
Claim 6
Dependent Claim
49 words
The optical modulator as recited in claim 5 wherein one of said members is fused silica doped with at least one or more oxides selected from the group consisting of titanium oxide, tantalum oxide, tin oxide, niobium oxide, zirconium oxide, aluminum oxide, lead oxide, and the rare earth oxides.
Claim 7
Dependent Claim
50 words
The optical modulator as recited in claim 5 wherein one of said members is fused silica doped with at least one material selected from the group consisting of leAd and the rare earth elements, whereby the Verdet constant of said waveguide is increased thereby increasing the efficiency of said modulator.
Claim 8
Dependent Claim
48 words
The optical modulator as recited in claim 5 wherein said cladding member is fused silica doped with at least one multivalent metal oxide selected from the group consisting of titanium oxide, tantalum oxide, tin oxide, niobium oxide, zirconium oxide, aluminum oxide, lead oxide, and the rare earth oxides.
Claim 9
Dependent Claim
45 words
The optical modulator as recited in claim 5 wherein said cladding member is undoped fused silica and the core is fused silica containing a dopant which provides a precise positive differential between the refractive index of said core member and that of the cladding member.
Claim 10
Dependent Claim
41 words
The optical modulator as recited in claim 10 wherein said core member consists of fused silica doped with oxides selected from the group consisting of lead oxides and the rare earth oxides whereby the Verdet constant of said waveguide is increased.
Claim 11
Dependent Claim
29 words
The optical modulator as recited in claim 11 wherein said core member is formed of 97 percent by weight of fused silica and a nominal 3 percent titanium dioxide.
Claim 12
Dependent Claim
37 words
The optical modulator as recited in claim 10 wherein said core member is formed of at least 85 percent by weight of fused silica and an effective amount up to 15 percent by weight of doping material.
Claim 13
Dependent Claim
73 words
The optical modulator as recited in claim 5 wherein said cladding layer and said core member are both composed of fused silica containing the same dopant, the proportion of the dopant in the fused silica of said core member exceeding that in the fused silica of said cladding member by a determined amount to provide a precise positive differential between the refractive index of said core member and that of said cladding member.
Claim 14
Dependent Claim
25 words
The optical modulator as recited in claim 5 wherein both said cladding member and said core member consist of fused silica doped with titanium oxide.
Claim 15
Dependent Claim
63 words
The optical modulator as recited in claim 5 wherein said cladding member and said core member are both composed of fused silica containing a dopant, the dopant in the core being different from that in the cladding member and being present in an amount sufficient to provide a precise positive differential between the refractive index of the core and that of the cladding.
Claim 16
Dependent Claim
128 words
An optical modulator for modulating a coherent beam of light initially polarized in a predetermined direction comprising in combination, an optical waveguide made of fused silica having a purity which transmits without substantial loss over a substantial length of said waveguide a limited number of modes of light, and means for generating a modulated magnetic field along the longitudinal axis of said waveguide such that the initial plane of polarization of any polarized beam of light introduced into said waveguide is rotated about said longitudinal axis by an amount proportional to the length of said magnetic field such that the direction of polarization of the light in said beam is modified in accordance with the modulation of said magnetic field as said light travels down said optical waveguide.
Claim 17
Dependent Claim
53 words
The optical modulator as recited in claim 17 wherein said fused silica is made by flame hydrolysis, which produces a high purity waveguide material, said high purity waveguide material reducing attenuation and depolarization to such an extent that polarization rotations in said waveguide are possible with magnetic fields as low as 100 oersteds.
Claim 18
Dependent Claim
48 words
The optical waveguide as recited in claim 18 wherein said waveguide includes a core member and a cladding member of fused silica, one of said members being doped so as to limit the number of modes said waveguide will transmit whereby depolarization of said light beam is limited.
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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) | 1976-09-03 | 1977-03-05 | 1977-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-03 | 1981-03-05 | 1981-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-03 | 1985-03-05 | 1985-09-04 | $7700.00 | Window Closed / Lapsed |