EP0054411A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Optical arrangement for optically coupling optical fibres
Assignee: Fujitsu Ltd
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Filing: 1981-12-10
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Granted: —
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Expires: 2001-12-10
Abstract
Abstract The optical device comprises tapered birefringent plates 32 and 32' the optical axes of which are rotated one with respect to the other around the direction of travel of light in the device. Between the tapered birefringent plates an element (33) for rotating the plane of polarisation of light passing therethrough is provided. The element (33) may be a 45° Faraday rotator, in which case the device acts as an optical isolator. Alternatively, the element (33) may be an electro-optic device, in which case the device acts as a phase difference-light intensity converter. The operation of the device is polarisation independent.
Inventors
- 👤 Masataka Shirasaki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 17:31
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/27; G02B6/2746; G02B5/00; G02B5/30; G02B6/42; G02B6/4201; G02B6/4204; G02B6/4207; G02B6/4208; G02B6/4209; G02F; G02F1/00; G02F1/01; G02F1/03; G02F1/0305; G02F1/0311; G02F1/09; G02F1/093; G02F2203/00; G02F2203/06
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
53 words
An optical device, comprising a first element, operable to change the plane of polarisation of light passing therethrough, interposed between a second element, operable to separate light of different polarisations, and a third element, operable to combine light of different polarisations, wherein the second and third elements are tapered plates of birefringent material.
Claim 2
Dependent Claim
53 words
An optical device, comprising a first element, operable to change the plane of polarisation of light passing therethrough, interposed between a second element, operable to separate light of different polarisations, and a third element, operable to combine light of different polarisations, wherein the second and third elements are tapered plates of birefringent material.
Claim 3
Dependent Claim
31 words
An optical device as claimed in claim 1, further comprising a first lens for directing light to the second element, and a second lens for receiving light from the third element.
Claim 4
Dependent Claim
47 words
An optical device as claimed in claim 2, further comprising a first optical fibre arranged so that light from an output end thereof passes to the first lens, and a second optical fibre arranged so that an input end thereof can receive light from the second lens.
Claim 5
Dependent Claim
53 words
An optical device as claimed in any preceding claim, wherein the optical axes of the tapered plates of birefringent material constituting the second and third elements are rotated, one with respect to the other, by an angle B (or θ + π/2) around a forward direction of travel of light in the device.
Claim 6
Dependent Claim
49 words
An optical device as claimed in claim 4, arranged so that when the plane of polarisation of light from the second element is rotated by θ (or θ + π/2) around the forward direction of travel by the first element, light emerges from the third element in parallel rays.
Claim 7
Dependent Claim
99 words
An optical device as claimed in claim 3, or any one of claims 4 and 5 when read as appended * to claim 3, wherein the first element is a 45° Faraday rotator, and the elements are arranged so that light travelling in the device in the.:forward direction, from the second element to the third element, is focussed on the input end of the second optical fibre by the second lens, and so that light travelling in the device in the reverse direction is not focussed on the output end of the first optical fibre by the first lens.
Claim 8
Dependent Claim
81 words
An optical device as claimed in claim 6, wherein the optical axis of the third element is rotated by 45°, around the forward direction, with respect to the optical axis of the second element, whereby for light travelling in the reverse direction ordinary and extraordinary rays emerging from the second element are so deflected, one with respect to the other, that they are focussed by the first lens at a point displaced from the output end of the first optical fibre.
Claim 9
Dependent Claim
147 words
An optical device as claimed in claim 4 or 5, when read as appended to claim 3, so arranged that light from the output end of the first optical fibre emerges from the first lens as parallel rays, and so that light focussed by the second lens, after passing through the second, first and third elements, enters the input end of the second fibre when the angle of rotation of the plane of polarisation provided by the first element is θ (or θ + π/2), and so that light is focussed by the second lens at a position spaced apart from the axis of the core of the second optical fibre by a distance greater than the diameter of the core of the second optical fibre, when the angle of rotation of the plane of polarisation provided by the first element is 8 + π/2 (or θ).
Claim 10
Dependent Claim
32 words
An optical device as claimed in claim 1, 2, 3, 4, 5 or 8 , wherein the first optical element comprises an electrooptic crystal, for example of zinc telluride or gallium arsenide.
Claim 11
Dependent Claim
40 words
An optical device as claimed in claim 3, or any one of claims 4 to 9 when read as appendant to claim 3, wherein the first and second optical fibres are both single mode fibres, or are both multi-mode fibres.
References Cited (Backward Citations)
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