Multirate FFH-OCDMA networks based on coherent advanced modulation formats

In this paper, we propose and evaluate the performance of a new scheme for multirate optical code-division multiple-access (OCDMA) networks based on coherent advanced modulation formats, namely binary and quadrature phase shift keying (BPSK and QPSK). The proposed scheme employs BPSK and QPSK modulation formats for low and high rate transmission users, respectively. In addition, we develop a general formalism that allows performance evaluation of legacy networks based on on-off keying (OOK) modulation format. We investigate how the coherent demodulation of encoded fast frequency hopping (FFH) signals under multiple access-interference (MAI) can improve the network performance. It is shown for the first time that simultaneous users of different transmission rates can surprisingly achieve BER levels in the error-free region.