A Fibre Optic Frequency Shifter Utilising Stimulated Brillouin Scattering In Birefringent Optical Fibre

Abstract

Frequency shifting is a well established technique to produce a heterodyne carrier at a frequency suitable for subsequent electronic demodulation. An acousto-optic Bragg cell is traditionally utilised to produce 40 or 80 MHz carriers, for example. However, these devices are generally incompatible with fibre optic systems due to the losses incurred in coupling into and out of monomode optical fibre.