All-optical phase and delay spectral encoding of signals with advanced modulation formats

We have investigated the application of a new all-optical cryptography technique to advanced modulation signals. Such technique is based on two-stage encoding scheme applied on narrowband spectral slices within composite dense wavelength division multiplexing (DWDM) signals. The first encoding stage implements spectral phase altering, while the second one imposes the cyphering delay to each spectral slice. Simulation results indicate that this coding technique can be successfully applied on advanced coded modulation formats with channel bit rates of 200 Gbps over metropolitan area networks.