Measuring effective birefringence in high-birefringence single-mode fibres using scanning Fabry-Perot interferometer and white light source

We report preliminary measurements of the linear effective birefringence in highly birefringent single-mode fibres using a Fabry-Perot interferometer: the comb spectrum obtained when the Fabry-Perot interferometer is illuminated by a collimated white light beam, is coupled into the fibre through a linear polariser. When scanning the Fabry-Perot mode interval, the degree of polarisation of the output shows strong resonances. Measuring the Fabry-Perot thickness at several successive resonances leads to a measurement of the linear effective birefringence and to a direct calibration of the fibre for gas sensing purposes.