Modified duobinary signal generation by means of a Mach-Zehnder intensity modulator as an example for integration of opto-electrical signal processing in optical broadband transmission systems

A new modulation scheme is presented utilizing the inherent signal shaping properties of counterpropagating (countp) optical and electrical signals in an optical Mach-Zehnder intensity modulator (MZM). The advantages of this method include the simplification of pulse shaping, spectral efficient modulation and DC-freedom of the signal to be processed by integration into the same single electro-optical device. The usefulness of this concept is verified by a transmission experiment at 1 Gbit/s.