Raw bit error rate (BER) measurements of a fully populated optical code division multiple access (CDMA) system

Optical CDMA is one of the few multiple access concepts which permit concurrent, non-blocking virtual channels. However, conventional approaches with linear codes induce stringent device requirements which stem from the bandwidth inefficiency, also denoted as the time penalty, of CDMA. In order to have the advantages of CDMA without its concommitant time penalty, we have been concentrating on multi-attribute CDMA. A previous paper reported on the analysis, design, and analog performance of bandwidth efficient matrix configurations. The research with analog transceivers validated the theory of constructing and implementing matrix codes. In the paper we go a step further and demonstrate the concurrent transmission of digital signals in a fully populated 4×4 optical matrix (CDMA) system by measuring its raw (no thresholding or processing) bit error rate. The authors measured a raw BER of 2.0*10E-9 at 155 Mb/s