Patent EP0378368A2 successfully refreshed from Google Patents.
EP0378368A2
Expired / Lapsed
EP
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Optical coupler with a fibre link between transceivers
Assignee: Leonardo UK Ltd
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Filing: 1990-01-09
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Granted: —
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Expires: 2010-01-09
Abstract
Abstract A bidirectional optical coupler has a single optical fibre link between two transceivers. Each transceiver includes a holographic optical element (HOE) (14), equivalent to a combination of lenses and a beam splitter; a source of monochromatic radiation (16); and a photodetector responsive to the radiation (18). Within a transceiver in the transmit mode, a divergent beam of radiation from the source is incident upon the HOE, and is diffracted, to form a pattern of interference fringes. Radiation is apparently focussed on the adjacent end of the optical fibre, and is transmitted by the fibre. At the other end of the optical fibre, the transceiver is in the receive mode, and the transmitted radiation is emitted as a divergent beam from the fibre, to be incident upon the HOE. The radiation is diffracted, and forms two angularly separated patterns of interference fringes. Thus, the radiation is apparently focussed upon the photodetector, (and upon the angularly separated, inoperable source).
Inventors
- 👤 James Moffat
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 13:05
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/40; G; G02; G02B; G02B6/00; G02B6/24; G02B6/42; G02B6/4201; G02B6/4204; G02B6/4246
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
252 words
An optical coupler has a single optical fibre link between two transceivers, each transceiver includes a holographic optical element, which holographic optical element is the equivalent of, at least, a predetermined combination of a plurality of lenses and a beam splitter, and each transceiver also includes at least one source of radiation of a predetermined wavelength, and at least one photodetector responsive to radiation transmitted within the system from said at least one source of the other, associated transceiver, the arrangement of each transceiver is so that, when in the transmit mode, radiation from said at least one source is transmitted by the holographic optical element, at least generally in one of two opposing directions through the holographic optical element, and is diffracted to form an interference fringe pattern, the radiation forming at least the highest order interference fringe of the pattern is incident upon the adjacent end of, and is transmitted by, the associated optical fibre, and when in the receive mode, radiation from said at least one source of the other, associated transceiver, transmitted by, and diverging from the adjacent end of, the associated optical fibre, is transmitted by the holographic optical element, at least generally in the other of said two opposing directions through the holographic optical element, and is diffracted to form at least two angularly separated interference fringe patterns, the radiation forming at least the highest order interference fringe of one of the angularly separated interference fringe patterns is incident upon, and is detected by, the photodetector.
Claim 2
Dependent Claim
252 words
An optical coupler has a single optical fibre link between two transceivers, each transceiver includes a holographic optical element, which holographic optical element is the equivalent of, at least, a predetermined combination of a plurality of lenses and a beam splitter, and each transceiver also includes at least one source of radiation of a predetermined wavelength, and at least one photodetector responsive to radiation transmitted within the system from said at least one source of the other, associated transceiver, the arrangement of each transceiver is so that, when in the transmit mode, radiation from said at least one source is transmitted by the holographic optical element, at least generally in one of two opposing directions through the holographic optical element, and is diffracted to form an interference fringe pattern, the radiation forming at least the highest order interference fringe of the pattern is incident upon the adjacent end of, and is transmitted by, the associated optical fibre, and when in the receive mode, radiation from said at least one source of the other, associated transceiver, transmitted by, and diverging from the adjacent end of, the associated optical fibre, is transmitted by the holographic optical element, at least generally in the other of said two opposing directions through the holographic optical element, and is diffracted to form at least two angularly separated interference fringe patterns, the radiation forming at least the highest order interference fringe of one of the angularly separated interference fringe patterns is incident upon, and is detected by, the photodetector.
Claim 3
Dependent Claim
46 words
An optical coupler as claimed in claim 1 in which each transceiver has one source, one photodetector, and a holographic optical element arranged to provide two angularly separated interference fringe patterns, and the fringe patterns are equi-angularly separated from a perpendicular to the holographic optical element.
Claim 4
Dependent Claim
60 words
An optical coupler as claimed in claim 1, or claim 2, in which each transceiver is provided within an hermetically sealed enclosure, the enclosure having a window for the radiation emitted from the, or each, source of the transceiver, and for radiation from the other transceiver, and received from the end of the optical fibre link adjacent to said transceiver.
Claim 5
Dependent Claim
23 words
An optical coupler as claimed in claim 3 in which each provided window is non-reflective, by the provision of a metallic coating thereon.
Claim 6
Dependent Claim
44 words
An optical coupler as claimed in claim 3, or claim 4, in which each provided window is secured to an adapter for the adjacent end of the optical fibre link, and the adapter forms part of the hermetically sealed enclosure for the associated transceiver.
Claim 7
Dependent Claim
17 words
An optical communications system including an optical coupler as claimed in any one of the preceding claims.
References Cited (Backward Citations)
No citation records indexed.
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