Polarisation-maintaining single-mode fibre with azimuthally inhomogeneous index profile

A new polarisation-maintaining single-mode fibre having a special class of azimuthally inhomogeneous index profile is proposed. Numerical results indicate that the modal birefringence ¿ß/k of 10¿5 is obtainable for two orthogonal HE11 modes. The value is large enough to maintain the polarisation state. It is also shown that a new deposition process based on the standard MCVD technique is applicable to fabricate the azimuthally inhomogeneous profile.