Patent EP0188889A2 successfully refreshed from Google Patents.
EP0188889A2
Expired / Lapsed
EP
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Light modulator comprising an optical fibre
Assignee: Plessey Overseas Ltd
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Filing: 1985-12-16
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Granted: —
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Expires: 2005-12-16
Abstract
Abstract A fibre optic modulator comprises an optical fibre 2 and a waveguide 10 of active material. The waveguide 10 is dimensioned such that any mode of the waveguide has a propogation constant which is separated from the propogation constant of the optical fibre mode by an amount equal to or greater than λ/L where λ is the wavelength of transmitted electromagnetic radiation in the mode of the optical fibre and L is the length of the effective portion of the waveguide of active material.
Inventors
- 👤 William James Stewart
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 17:37
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/011; G02F1/0115; G02F1/0118
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
118 words
A modulator for electromagnetic radiation, the modulator comprising an optical fibre (2), having an optical fibre mode, for conveying electromagnetic radiation, and a waveguide (10) of active material, in optical communication with the optical fibre and responsive to an applied field for modulating electromagnetic radiation in the active material in optical communication with the optical fibre (2), characterised in that the waveguide (10) of active material has a propogation constant separated from that of the optical fibre mode by an amount equal to or greater than λ/L where λ is the wavelength of the electromagnetic radiation in the mode of the optical fibre and L is the length of the effective portion of the waveguide of active material.
Claim 2
Dependent Claim
118 words
A modulator for electromagnetic radiation, the modulator comprising an optical fibre (2), having an optical fibre mode, for conveying electromagnetic radiation, and a waveguide (10) of active material, in optical communication with the optical fibre and responsive to an applied field for modulating electromagnetic radiation in the active material in optical communication with the optical fibre (2), characterised in that the waveguide (10) of active material has a propogation constant separated from that of the optical fibre mode by an amount equal to or greater than λ/L where λ is the wavelength of the electromagnetic radiation in the mode of the optical fibre and L is the length of the effective portion of the waveguide of active material.
Claim 3
Dependent Claim
40 words
A modulator according to claim 1 characterised in that the waveguide (10) comprises a stripe of active material, the longitudinal axis of the stripe of active material being arranged substantially parallel to the longitudinal axis of the optical fibre (2).
Claim 4
Dependent Claim
18 words
A modulator according to claim 1 characterised in that the waveguide (10) comprises a slab of active material.
Claim 5
Dependent Claim
43 words
A modulator according to any one of claims 1 to 3 characterised in that the waveguide (10) of active material comprises a backing medium (12), the backing medium (12) having a refractive index lower than the refractive index of the optical fibre (2).
Claim 6
Dependent Claim
15 words
A modulator according to claim 4 characterised in that the backing medium (12) comprises air.
Claim 7
Dependent Claim
17 words
A modulator according to claim 4 characterised in that the backing medium (12) comprises a metal layer.
Claim 8
Dependent Claim
46 words
A modulator according to any one of claims 4 to 6 charaterised in that the dimensions of the waveguide (10) of active material and the refractive index of the backing medium (12) are arranged such that there is no mode in the waveguide of active material.
Claim 9
Dependent Claim
19 words
A modulator according to any one of the preceding claims characterised in that the active material comprises lithium niobate.
Claim 10
Dependent Claim
23 words
A modulator according to any one of claims 1 to 8 characterised in that the active material comprises Lanthanum doped lead zirconate titanate.
Claim 11
Dependent Claim
28 words
A modulator according to any one of the preceding claims characterised by a pair of electrodes for providing an electric field within the waveguide (10) of active material.
References Cited (Backward Citations)
No citation records indexed.
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