Early/Late Gate, Binary-PPM, and Data-Rate-Doubling Technologies for Optical CDMA

Optical Code Division Multiple Access (OCDMA) is compatibility with bursty, asynchronous communication protocols, and therefore supports new capabilities in (1) access, metropolitan, and fiber-to-the-premise (FTTP) networking; (2) avionics integration; and (3) covert communications (steganography). The impediments to OCDMA achieving this potential include (a) complexity of implementation and (b) multi-access interference (MAI) in the less complex implementations. To resolve these problems we have been developing low complexity, high spectral efficiency OCDMA system concepts that lend themselves to standardization. But it leaves the issue of MAI reduction. Here we propose a simple technique, early/late gate signal processing, borrowed from radar, to estimate and subtract the MAI in support of market objective (1). We further propose Manchester coding (binary-PPM) in conjunction with OCDMA to support bursty, multi-rate, variable packet size transmission in support of market objective (2). Finally, we propose rate-doubling techniques to develop the capability to support 1.25 to 2.5 Gb/s transmission with a system conceived for 1.25 Gb/s in support of market objectives (1)-(3). All three of these techniques/technologies can be developed and demonstrated on an OCDMA Technology Demonstrator developed on DOE SBIR Phase II and NSF Phase I Grants. This Project is based on adopting the NSF Phase I project.