8 km-long polarisation-maintaining fibre with highly stable polarisation state

Abstract

A new preform fabrication technique for realising long lengths of polarisation-maintaining optical fibres is described. The technique is shown to produce stress-induced birefringent fibres with symmetry and uniformity along the length in the stress-applying parts. The resultant 8.3 km-long fibre whose relative refractive-index difference is 0.6% has been obtained with a crosstalk of −23 dB at 1.15 μm wavelength, where the loss is 1.7 dB/km.