Fibre optic cable responsive to microbending forces
First Claim
1. A fibre-optic cable responsive to microbending forces comprising at least one fibre which forms part of a pressure responsive device, in which a radiation source located at one end of the cable introduces light into the fibre and a sensor measures the intensity of the light transmitted through the fibre, a casing on said fibre, and at least one longitudinally extending element between the casing and the fibre for introducing a periodic disturbance along at least a part of the fibre in response to application of pressure to the cable, said periodic disturbance having a critical periodic length which corresponds to maximum attenuation of the light introduced in said fibre, said element extending longitudinally along the fibre in abutment therewith and being deformed so as to provide isolated contact regions along the surface of the fibre at a determined spacing substantially coinciding with said critical periodic length for the periodic disturbance.
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Accused Products
Abstract
A fibre-optic cable responsive to microbending and forming part of a device for measuring pressure in accordance with the principle of creating a periodic mechanical disturbance in the fibre. The cable comprises a fibre (F) having a core (C) and a core-sheathing (M). An elongated element in the form of a twisted filament (T1, T2) or a twisted band (B) extends along the fibre, and a primary shield (H) encases the fibre and the twisted element such that the twisted element contacts the sheathing at periodically spaced separate regions.
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Citations
12 Claims
- 1. A fibre-optic cable responsive to microbending forces comprising at least one fibre which forms part of a pressure responsive device, in which a radiation source located at one end of the cable introduces light into the fibre and a sensor measures the intensity of the light transmitted through the fibre, a casing on said fibre, and at least one longitudinally extending element between the casing and the fibre for introducing a periodic disturbance along at least a part of the fibre in response to application of pressure to the cable, said periodic disturbance having a critical periodic length which corresponds to maximum attenuation of the light introduced in said fibre, said element extending longitudinally along the fibre in abutment therewith and being deformed so as to provide isolated contact regions along the surface of the fibre at a determined spacing substantially coinciding with said critical periodic length for the periodic disturbance.
Specification