Demonstration of birefringent optical fibre frequency shifter employing torsional acoustic waves

Abstract

A fibre-optic frequency shifter utilising torsional acoustic waves to produce a travelling perturbation which couples the polarisation modes of a linearly bircfringent optical fibre is demonstrated. The shift in optical frequency was 3.195 MHz and an optical coupling efficiency of 6% was obtained with 780 mW of electrical power.