EP0307244A1
Expired / Lapsed
EP
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An optical space switch
Assignee: British Telecommunications PLC
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Filing: 1988-09-09
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Granted: —
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Expires: 2008-09-09
Abstract
Abstract An optical space switch comprising an optical output (O); three optical deflection stages (S) each comprising a twisted-nematic liquid crystal polarisation rotator (R) responsive to a respective bi-state control signal and a calcite crystal deflection means (D) for selectively deflecting optical signals according to their polarisation; the deflection stages (D) being serially arranged to define eight distinct source locations from where an optical signal is selectively deflectable successively by the deflection stages (D) to the optical output (O), a distinct combination of states of the three control signals corresponding to each location eight optical sources (I) are located at one of the source locations. Each input is formed from an array of fibres so as to be capable of launching an optical signal which is spatially modulated transverse to the signal propagation direction. Each deflection stage (S) preserves the spatial integrity of the deflected optical signals.
Inventors
- 👤 Peter Healey
- 👤 Stephen Robert Mallinson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 09:36
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/29; G02F1/31; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/28; G02B6/2804; G02B6/2817
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
126 words
An optical space switch comprising: an optical output; n optical deflection stages each comprising a polarisation rotator responsive to a respective control signal to rotate the polarisation of an optical signal through 90°, and a deflection means for selectively deflecting optical signals according to their polarisation; the n deflection stages being serially arranged to define 2 n distinct source locations from where an optical signal is selectively deflectable successively by the n deflection stages to the optical output, a distinct combination of states of the n control signals corresponding to each location; a plurality of up to 2 n optical sources each located at one of the 2 n source locations; and in which each deflection stage preserves the spatial integrity of the deflected optical signals.
Claim 2
Dependent Claim
126 words
An optical space switch comprising: an optical output; n optical deflection stages each comprising a polarisation rotator responsive to a respective control signal to rotate the polarisation of an optical signal through 90°, and a deflection means for selectively deflecting optical signals according to their polarisation; the n deflection stages being serially arranged to define 2 n distinct source locations from where an optical signal is selectively deflectable successively by the n deflection stages to the optical output, a distinct combination of states of the n control signals corresponding to each location; a plurality of up to 2 n optical sources each located at one of the 2 n source locations; and in which each deflection stage preserves the spatial integrity of the deflected optical signals.
Claim 3
Dependent Claim
16 words
A switch as claimed in claim 1 in which the deflection means comprises a birefringent material.
Claim 4
Dependent Claim
14 words
A switch as claimed in claim 2 in which the birefringent material is calcite.
Claim 5
Dependent Claim
20 words
A switch as claimed in claim 1 in which the deflection means comprises a combination of polarisation beamsplitters and prisms.
Claim 6
Dependent Claim
18 words
A switch as claimed in any preceding claim in which the polarisation rotator is a twisted-nematic liquid crystal.
Claim 7
Dependent Claim
15 words
A switch as claimed in any preceding claim in which the optical signals are collimated.
Claim 8
Dependent Claim
43 words
A switch as claimed in any one of claims 1 to 6 in which the optical sources provide divergent optical signals and there is included a means for directing the optical signal which emerges axially from the final deflection stage to the output.
Claim 9
Dependent Claim
26 words
A switch as claimed in any preceding claim in which the polarisation rotator is positioned at the common focal point of a pair of convergent lenses.
Claim 10
Dependent Claim
30 words
A switch as claimed in any preceding claim in which each optical source is capable of launching an optical signal which is spatially modulated transverse to the signal propagation direction.
Claim 11
Dependent Claim
19 words
A switch as claimed in any preceding claim is which the optical sources comprise a plurality of optical fibres.
Claim 12
Dependent Claim
21 words
A switch as claimed in any preceding claim in which the optical sources comprise a plurality of individually modulated optical emitters.
Claim 13
Dependent Claim
28 words
A switch as claimed in any preceding claims in which the optical sources emit an optical signal whose spatial modulation is representative of at least one binary word.
Claim 14
Dependent Claim
15 words
A generalised optical connection network including an optical switch as claimed in any preceding claim.
Claim 15
Dependent Claim
15 words
A permutation optical connection network including an optical switch as claimed in any preceding claim.
Claim 16
Dependent Claim
6 words
A optical switch as hereinbefore described.
Claim 17
Dependent Claim
6 words
A optical switch as hereinbefore described.
References Cited (Backward Citations)
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