Abstract

Several recent works,^1-3 have pointed out the benefit expected from duobinary coding⁴ for 10-Gbit/s TDM transmission over standard dispersive fibers because of the spectral bandwidth reduction with respect to conventional NRZ format. The idea was that, because the chromatic dispersion limit was related to the signal bandwidth, the ≈65-km maximum transmission distance over standard fiber should be improved. Two schemes have been proposed. The first one considers a three-optical intensity level coding. It was shown experimentally¹ and by numerical simulations⁵ that about 100 km could be reached. The second scheme consists in coding the phase of the optical wave^2-3 but no simulation of the propagation of such a wave was performed. Here, we show numerically and experimentally that the spectral bandwidth of the sequence is not the relevant parameter to assess the dispersion tolerance.

© 1996 Optical Society of America