Double all-optical encryption of M-QAM signals based on spectrally sliced encoding keys

The ever-growing demand for optical network security can be addressed by data encryption at different network layers. In this work, we consider all-optical cryptography technique that applies a spectral phase change and delay encoding on spectrum slices of a specified WDM channel. In this case we have investigated a novel approach where signals are double encrypted to achieve an enhanced degree of security. Simulation results indicate that such double cyphering scheme can be applied to high data-rate M-QAM signals propagating in metro/regional networks.