High speed and secure optical CDMA-based passive optical networks

One bi-directional passive optical network (PON) based on optical code-division multiple access with interference elimination is proposed. By combining with wavelength division multiplexing (WDM) technique, the proposed scheme alleviates the noise arising during photo-detecting process in the PON. Therefore, the bit error rate performance is improved, which is demonstrated by the results of performance analysis. In addition, simple and low cost encoding/decoding structures with small sizes in the optical line terminal are proposed, and they can cooperate with the dynamic codeword assignment scheme to provide a more secure signal transmission in the PONs.