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 correlator corresponds to the difference between agreements and disagreements, thus mimicking the output obtained in classical electrical code-division multiple-access (CDMA) systems. The approach is described through a tapped delay line concept, but if viewed as a means of additional encoding, it can be realized using ladder networks or other architectures. Synchronons CDMA (S/CDMA) networks lend themselves particularly well for implementation through this architecture. The approach, in tandem with special codes defined as double balanced codes, allows detection of the autocorrelation peak without interference from unwanted users. Proof-of-principle experimental verification of the architecture for a 2-b correlation at 50 Mb/s and computer simulations of a multiuser network are presented.