Study of 16/spl times/20 Gsymb/s WDM dispersion supported transmission systems using different line-codes

In this contribution we assess and compare the performance of 16/spl times/20 Gsymb/s WDM dispersion supported transmission systems, considering three different line-codes: binary NRZ, duobinary and 4-level. The demultiplexing operation is performed using uniform fiber Bragg gratings. The capability of 320 Gbit/s (16/spl times/20 Gbit/s) WDM dispersion supported transmission systems over 65 km and 100 km, using respectively binary and duobinary coding, is demonstrated. It is also verified the feasibility of such a system using 4-level coding at 640 Gbit/s (16/spl times/40 Gbit/s), for a fiber length of 45 km. High density WDM signal with approximately 1 bit/s/Hz spectrum efficiency is produced by optical 4-level coding.