We design various tapered photonic crystal fibers (PCFs) , namely, hexagonal tapered PCF (H-TPCF), octagonal tapered PCF (O-TPCF) and decagonal tapered PCF (D-TPCF) for generating self-similar ultrashort pulses (USPs) and stretched pulses . Here, we report on pulse compression as well as pulse stretching using the above mentioned PCFs wherein both dispersion and nonlinear profiles vary exponentially. Of these PCFs, we use dispersion decreasing PCFs for pulse compression process and dispersion increasing PCFs for pulse stretching process. From the detailed analysis, we find that H-TPCFs could generate high quality USPs with more compression percentage whereas D-TPCFs could produce high quality stretched pulses with more stretching percentage.