Evaluation of transmission characteristics of chirped DFB lasers indispersive optical fiber

Experimental and analytical results are presented for pulse distortion and receiver penalty associated with wavelength chirp of 1.5 μm distributed feedback (DFB) lasers in the presence of fiber dispersion. An approximate analytical model for dispersion penalty due to chirp is given and shown to provide reasonable agreement with the experimental results obtained for digital transmission at 1.7 Gb/s. The model captures the important features of chirp that lead to dispersion penalty, such as the maximum wavelength excursion, the chirping time, and the energy content at the leading edge of the pulse during chirp. The utility of the model is that the parameters used in it can be readily obtained from single experimental measurements. The limitations of the model are also discussed