Polarisation independent all-optical demultiplexing using four wave mixing in dispersion shifted fibre

A novel polarisation independent demultiplexer based on four wave mixing in a dispersion shifted fibre is proposed using a short, highly birefringent fibre in a forward and backward propagation scheme to allow polarisation diversity operation. The device has been tested with a 4/spl times/10 Gbit/s optical time division multiplexing transmitter. Polarisation dependency is less than 0.5 dB and the BER measurement does not show any floor down to 10/sup -13/.