System performance implications of laser chirp for long haul high bit rate direct detection optical fibre communications

Long-distance high-data-rate systems can be impaired by interactions between laser wavelength chirp and the generally nonzero chromatic dispersion of monomode fibers. Strategies suitable for estimating the chirp-induced power penalty in direct detection optical fiber systems are outlined. A SPICE2 equivalent circuit model of a single-frequency laser diode is used to obtain light intensity and wavelength chirp profiles for representative data sequences. These are used together with two computer-based models for chirp dispersion interaction, which produce similar results for the range of values considered. Good agreement is obtained with reported experimental power penalties.<>