EP0042907A1
Expired / Lapsed
EP
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Optical switch
Assignee: International Business Machines Corp
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Filing: 1981-03-06
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Granted: —
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Expires: 2001-03-06
Abstract
Abstract An optical switch (10) is interposed between two light paths (12,14) comprising optical fibres (20,22) and focusing elements (24,26). The switch includes a toroidal enclosure (28) filled with a transparent fluid 40 and a ferrofluid pellet (30) whose rest position is below the space between the light paths which are coupled through the transparent fluid. Electrical coils (32,34) surround the focusing elements and are energisable to generate a magnetic field to move the ferrofluid pellet to a position between the light paths, in which the opacity of the ferrofluid uncouples the light paths. Additional coils (36,38) may be energised to return the ferrofluid pellet upon de-energisation of the coils (32,34).
Inventors
- 👤 Michael John Brady
- 👤 Lawrence Vincent Gregor
- 👤 Mark Johnson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 19:50
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/35; G02B6/3564; G02B6/3568; G02B6/3572; G02B26/00; G02B26/004; G02B6/3502; G02B6/351; G02B6/353; G02B6/3538; G02B6/354; G02B6/3544; G02B6/3548; G02B6/355; G02B6/3552
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
80 words
1 An optical switch comprising at least two light paths (12,14;42,46;72,82,80) characterised by ferrofluid means (30;50;86) capable of assuming at least two different configurations, a first and second of the light paths being coupled together when the ferrofluid means is in a first of the configurations and not coupled together when the ferrofluid means is in a second of the configurations, and controllable magnetic field means (32,34;60;90) for causing the ferrofluid means to assume a selected one of the configurations.
Claim 2
Dependent Claim
80 words
1 An optical switch comprising at least two light paths (12,14;42,46;72,82,80) characterised by ferrofluid means (30;50;86) capable of assuming at least two different configurations, a first and second of the light paths being coupled together when the ferrofluid means is in a first of the configurations and not coupled together when the ferrofluid means is in a second of the configurations, and controllable magnetic field means (32,34;60;90) for causing the ferrofluid means to assume a selected one of the configurations.
Claim 3
Dependent Claim
78 words
2 A switch according to claim 1, in which the first and second light paths are in spaced alignment with each other, so that light will travel from one of the paths through a space between the paths and into the other of the paths when the space contains a medium transparent to the light, the first configuration corresponding to the space containing a transparent medium and the second configuration corresponding to the space containing an opaque ferrofluid.
Claim 4
Dependent Claim
21 words
3 A switch according to claim 2, in which the opaque ferrofluid is movable into the space by a magnetic field.
Claim 5
Dependent Claim
24 words
4 A switch according to claim 2 or 3, in which the opaque ferrofluid is movable out of the space by a magnetic field.
Claim 6
Dependent Claim
47 words
5 A switch according to claim 2, 3 or 4, in which the space corresponds to a region with an enclosure containing both an opaque ferrofluid and a transparent fluid, the position of the ferrofluid being controlled by a magnetic field generated by the magnetic field means.
Claim 7
Dependent Claim
25 words
6 A switch according to claim 1, which includes N pairs of light paths, the ferrofluid means being capable of assuming 2 N different configurations.
Claim 8
Dependent Claim
25 words
7 A switch according to claim 1 or 6 in which the ferrofluid means is brought into different configurations by moving ferrofluid to different positions.
Claim 9
Dependent Claim
23 words
8 A switch according to claim 7, in which the ferrofluid is movable by a magnetic field generated by the magnetic field means.
Claim 10
Dependent Claim
35 words
9 A switch according to claim 1, comprising three light paths (72,82,80), the first light path (72) being coupled to a third light path (80) when the ferrofluid means (86) is in the second configuration.
Claim 11
Dependent Claim
29 words
10 A switch according to claim 1 or 9, in which the ferrofluid means is brought into different configurations by changing the distribution of magnetic particles within a ferrofluid.
Claim 12
Dependent Claim
27 words
11 A switch according to claim 10 in which the ferrofluid does not substantially change position when the distribution of magnetic particles within the ferrofluid is changed.
Claim 13
Dependent Claim
31 words
12 A switch according to claim 10 or 11, in which the distribution of magnetic particles within the ferrofluid is changed by a magnetic field generated by the magnetic field means.
Claim 14
Dependent Claim
29 words
13 A switch according to claim 10, 11 or 12, in which the change of distribution of magnetic particles within the ferrofluid changes the density distribution of the ferrofluid.
Claim 15
Dependent Claim
41 words
14 A switch according to claim 13 in which the change of density distribution of the ferrofluid changes the distribution of buoyancy forces of the ferrofluid upon a movable member in contact with the ferrofluid, thus causing movement of the member.
Claim 16
Dependent Claim
18 words
15 A switch according to claim 14, in which the movable member is a cantilevered first optical fibre.
Claim 17
Dependent Claim
49 words
16 A switch according to claim 15, in which the cantilevered first optical fibre may be controllably brought by the ferrofluid into a predetermined position with respect to a second optical fibre, the predetermined position corresponding to either an optical coupling or uncoupling of the first and second fibres.
Claim 18
Dependent Claim
31 words
17 A switch according to claim 16, in which the cantilevered first optical fibre tends to be brought away from the predetermined position by elastic deformation forces of the cantilevered fibre.
Claim 19
Dependent Claim
17 words
18 A switch according to any preceding claim, in which each light path comprises an optical fibre.
Claim 20
Dependent Claim
35 words
19 A switch according to claim 18, in which at least one of the light paths further comprises a focusing element for directing light from the one path to another one of the light paths.
Claim 21
Dependent Claim
21 words
20 A switch according to any preceding claim in which the controllable magnetic field means comprises at least one electromagnet element.
References Cited (Backward Citations)
US4121884A
Cited
GB2030319A
Cited
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