18 Gchips/s Electronic CDMA for Low-Cost Optical Access Networks

This paper reports, for the first time, the coding and decoding of code-division multiple-access (CDMA) signals for use in optical access networks using electronic transversal filters at a at achip rate of 18 Gchips/s, a ninefold improvement over previous demonstrations. We demonstrate a 2-user ECDMA system. The use of 7-chip transversal filters gives a potential for 7 users, where each user has a data rate of 1.25 Gb/s. This is comparable to typical all-optical CDMA systems but with potentially lower cost, power consumption and complexity. Error-free transmission of a 1.25 Gb/s electronic CDMA user signal, with and without a single interferer, over 10 km of single-mode fiber is reported for the first time.