US3620599A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Nonpolarizing wire-grid diffraction-type optical attenuator
Assignee: AT&T Inc
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Filing: 1969-06-30
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Granted: 1971-11-16
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Expires: 1989-06-30
Abstract
Abstract A continuously variable optical attenuator of the wire-grid type is disclosed in which the wire diameter and the spacings therebetween are from one to three orders of magnitude greater than the wavelength of the optical radiation to be attenuated and which operates upon principles of diffraction. Even at high attenuation factors, the attenuation does not depend significantly upon the polarization of the input optical radiation.
Inventors
- 👤 Arthur Ashkin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 21:51
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/18; G02B5/1828; G02B5/1866
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
107 words
An optical attenuator of the type employing a grid of parallel reflective wires and being mounted for rotation about an axis parallel to said wires, characterized in that said wires have cross-sectional dimensions between one and three orders of magnitude larger than the wavelength of the optical radiation to be attenuated and have spacings therebetween which are between one and three orders of magnitude larger than the wavelength of the radiation, and including means in tandem with said grid in said attenuator for selectively transmitting only a beam of a single diffraction order and for blocking beams of all other diffraction orders from transmission through said attenuator.
Claim 2
Dependent Claim
107 words
An optical attenuator of the type employing a grid of parallel reflective wires and being mounted for rotation about an axis parallel to said wires, characterized in that said wires have cross-sectional dimensions between one and three orders of magnitude larger than the wavelength of the optical radiation to be attenuated and have spacings therebetween which are between one and three orders of magnitude larger than the wavelength of the radiation, and including means in tandem with said grid in said attenuator for selectively transmitting only a beam of a single diffraction order and for blocking beams of all other diffraction orders from transmission through said attenuator.
Claim 3
Dependent Claim
98 words
An optical attenuator of the type described in claim 1 in which the transmitting means includes an optically absorbing enclosure surrounding the grid of attenuator wires and having an input aperture and an output aperture aligned along an axis intersecting the axis rotation of the grid, said grid being separated from said output aperture by a distance at least as large as the beam width times the actual spacing of the wires divided by the wavelength of the radiation to be attenuated, whereby the first order and higher order diffracted beams will be blocked from the output aperture.
Claim 4
Dependent Claim
25 words
An optical attenuator of the type claimed in claim 2 including means for cooling the enclosure to a temperature below the temperature of the grid.
Claim 5
Dependent Claim
26 words
An optical attenuator of the type claimed in claim 1 in which the wires are hollow and including Means for flowing a coolant through said wires.
Claim 6
Dependent Claim
56 words
An optical attenuator of the type claimed in claim 1 in which the wires have circular cross sections of diameter between 10 and 1,000 times the wavelength of the optical radiation to be attenuated and the orthogonal distance between the wires is between 20 and 1,000 times the wavelength of the optical radiation to be attenuated.
Claim 7
Dependent Claim
51 words
An optical attenuator of the type claimed in claim 5 in which the wires have cross sections of diameter about 15 times the wavelength of the optical radiation to be attenuated and the orthogonal distance between the wires is about 35 times the wavelength of the optical radiation to be attenuated.
References Cited (Backward Citations)
US2287598A
Cited
US2821109A
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US3046839A
Cited
US3291871A
Cited
US3413476A
Cited
US3474354A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-15 | 1975-05-17 | 1975-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-15 | 1979-05-17 | 1979-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-15 | 1983-05-17 | 1983-11-16 | $7700.00 | Window Closed / Lapsed |