Design of FBG-based ultra-narrow asymmetric filter for transmission with 0.8 bit/s/Hz spectral efficiency without polarisation multiplexing

We propose a novel approach to ultra-narrow optical filtering based on a specially designed slightly asymmetric filter, which can be fabricated using fibre Bragg gratings. A feasibility of 8×40Gbit/s DWDM RZ transmission with 0.8bit/s/Hz spectral efficiency (without polarisation multiplexing) over 1280 km of SMF/DCF link without FEC has been confirmed by numerical modelling.