Linear/Measured chirped Gaussian pulse propagation is simulated at various data rates transmission in the presence of group velocity dispersion without amplification unit. The power variations (PVs) vs. frequency, time period are also clarified after 250 km fiber channel length and 10 Gb/s bit rate (BR) of for Gaussian pulse generators with linear chirp factor of 2 rad/s, measured chirp factor (alpha parameter of 2 rad/W, Adiabatic chirp of 10 s −1 ). Moreover the overall total light power after fiber, the overall total electrical power after APD receiver are studied and clarified for Gaussian pulse generators with linear chirp, measured chirp factor. PVs vs. frequency, time period are simulated after APD receiver for Gaussian pulse generators with linear chirp, measured chirp factor. Maximum signal amplitude variations vs. time after APD receiver for Gaussian pulse generators with linear chirp, measured chirp factor are also clarified with the numerical simulation results.