Reconfigurable encoder-decoder structure for 2D OCDMA systems

We propose and experimentally demonstrate a 2.5Gbits/s reconfigurable encoder-decoder structure that can be used for two-dimensional (time-wavelength) optical code-division multiple access (OCDMA) systems. Each encoder and decoder is constructed using a single opto-very-large-scale-integrated (VLSI) processor for encoding N users, thus eliminating the need for optical switching between encoders. The opto-VLSI processor synthesizes wavelength codewords through computer-generated digital phase holograms, which can switch the wavelength through different true-time-delay paths. The encoded signal can be successfully retrieved at the decoder side only when the digital phase holograms of the encoder and the decoder are matched. The system performance is measured in terms of the generated autocorrelation and cross-correlation functions as well as eye diagrams.