In this paper we propose a new multirate optical network based on a hybrid S-ALOHA/overlapped-CDMA system as an effective way of integrating multi-class traffic. The key issue in this proposal is to exploit the potential of the optical overlapped CDMA using fiber Bragg grating when jointly used with the S-ALOHA protocol in a link layer. The newly proposed system is modeled using general Markov chain from which both the system throughput and the average packet delay are derived. Our system is then compared to the classical S-ALOHA/variable processing gain (VPG) CDMA system. Numerical results show that our system outperforms the latter especially at high transmission rates