Abstract

It has been reported that appropriate chirp of an external modulator in an IM/ DD system can reduce the chromatic dispersion penalty relative to the chirpless case for middle-length transmission systems.^1,2 However, in long haul, high-speed optically amplified IM/DD systems, the major system impairment is caused by the combined effect of chromatic dispersion and self-phase modulation (SPM) due to the nonlinear Kerr effect.³ In this paper, we investigate the influence of external modulator chirp on system performance in the presence of chromatic dispersion and SPM, and in particular, we present the performance improvement attainable by using appropriate modulator chirp combined with optimum receiver filter design.

© 1994 IEEE