Optimized bandwidth-limited duobinary coding format for ultra dense WDM systems

By varying simultaneously the bandwidths of electrical transmitter filter, multiplexer and demultiplexer, the system performance of several duobinary coding formats is optimized for 40 Gbit/s/channel ultra dense wavelength division multiplexing (UDWDM) system with 50 GHz of channel spacing after 4/spl times/80 km of transmission. It is shown that bandwidth-limited (BL) duobinary generation schemes with optimized electrical transmitter filter bandwidth can achieve a Q-factor improvement of 1.4 dB over BL-conventional duobinary coding schemes. Moreover, the optimized BL-duobinary format achieves a better UDWDM system performance than BL-phase-shaped binary transmission, for which a capacity/spl times/distance record was demonstrated.