INCOHERENT ALL-OPTICAL CODE RECOGNITION WITH BALANCED DETECTION

A novel incoherent guided wave optoelectronic correlator architecture for performing code recognition is introduced. The output of this corr elator corresponds to the difference between agreements and disagreeme nts, thus mimicking the output obtained in classical electrical code-d ivision multiple-access (CDMA) systems. The approach is described thro ugh a tapped delay line concept, but if viewed as a means of additiona l encoding, it can be realized using ladder networks or other architec tures. Synchronous CDMA (S/CDMA) networks lend themselves particularly well for implementation through this architecture. The approach, in t andem with special codes defined as double balanced codes, allows dete ction of the autocorrelation peak without interference from unwanted u sers. Proof-of-principle experimental verification of the architecture for a 2-b correlation at 50 Mb/s and computer simulations of a multiu ser network are presented.