| 摘要 |
A current sensor which makes use of the Faraday effect, which is patterned o n a Sagnac interferometer and which employs a coil of spun birefringent optical fibre for sensing the magnitude of curre nt flowing through a conductor about which the sensor is, in use, located. The sensor in its preferred form comprises a coil (10) of spun single mode birefringent optical fibre (11), the coil being arranged to locate about a conductor (12) through which current f low occurs. A beam splitting device (22) in the form of a 3*3 coupler is coupled with the ends of the coil fibre and is arranged to launch counter-propagating light beams into the respective ends of the coil fibre. A lasing light source (16) is optically c oupled to the beam splitting device by way of a 2*2 coup ler (21), and detectors (18) which are arranged to detect a phase shift between the polarisation modes of the counter-propagated light beams are optically coupled to the ends of the coil fibre by way of the beam splitting device.
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