Longitudinal spatial characterisation of optical fibre erbium distributed feedback laser under the motion of steady magnetic field

Yao, Yuan and Flockhart, Gordon M. H.; López-Higuera, José Miguel and Jones, Julian and López-Amo, Manuel and Santos, José Luis, eds. (2014) Longitudinal spatial characterisation of optical fibre erbium distributed feedback laser under the motion of steady magnetic field. In: 23rd International Conference on Optical Fibre Sensors. Proceedings of the SPIE . SPIE, ESP. ISBN 9781628411751

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    Abstract

    The spatial sensitivity of an erbium doped optical fibre distributed feedback (DFB) laser to an external magnetic field is reported. Intrinsic birefringence of the laser cavity allows lasing in two orthogonal modes. The polarisation beat frequency between these modes is sensitive to magnetic fields aligned along the axis of the optical fibre due to the Faraday effect. The interaction of magnetic field, generated by a permanent magnet, with the spatial mode profile of the laser is investigated. Experimental measurements show a 3.82 MHz change in the beat frequency when a permanent magnet is scanned along the fibre laser.