Abstract

There is a clear requirement emerging in the design of future metropolitan and access networks for broadband access techniques capable of supporting the required fine channel granularity and the bursty nature of packet-based services. Conventional multiplexing techniques such as DWDM and OTDM are not best suited for use within such networks from both technological and economic perspectives, and further research into other suitable transmission/distribution techniques is required. Optical Code Division Multiple Access (OCDMA) is one such emerging technique that promises a variety of attractive features suitable for such networks. These features include asynchronous operation, flexible bandwidth management, improved system security, and the potential for higher levels of connectivity and network scalability. Recently, Super-structured Fibre Bragg Grating (SSFBG) technology has been shown to provide an attractive and highly flexible route to produce high performance, and potentially low-cost, code generation and recognition components as required for Direct Sequence (DS-) OCDMA systems. Whilst impressive results on the basic code generation and recognition processes have been obtained,¹ little attention has been paid to the more practical issues of system design and limits to capacity. In particular, most experiments to date have employed expensive and impractical ultrashort pulse seed sources and detection schemes,² and have been limited in terms of channel numbers. Moreover, little systematic experimental work has been done on the deleterious impact of Multiple Access Interference (MAI) noise as the number of users is increased.

© 2002 Optical Society of America