Elimination of polarization degeneracy in round waveguides.

We show how to design a round optical fiber so that it is effectively single moded, with no polarization degeneracy. Such fibers would be free from the consequences of polarization degeneracy or near degeneracy - phenomena such as polarization fading in interferometry, and polarization mode dispersion - and so may offer an alternative to polarization maintaining fibers for the avoidance of these phenomena. The design presented builds on an earlier observation of polarization selective refection in Bragg fibers.