This paper shows simulations of an all-fiber fast optical code division multiple access communications system (OCDMA), using strong apodized fiber Bragg gratings (FBGs) arrays as passive encoding-decoding devices. Auto and cross-correlation functions of the user signals, and bit error rate (BER) were used as evaluation criteria. Through numerical analysis, we demonstrated that when strong Bragg gratings are used the performance of the system is increased. We obtain the BER performance for strong gratings and compare results in various cases.