Double security level in a telecommunication system based on phase coding and false data transmission

A new communication system exhibiting a double security level is demonstrated. Information coding is based on relative phase changes between consecutive time intervals of the light emitted from a highly coherent CW source. An imbalanced Mach-Zehnder interferometer whose time delay matches the intervals duration is used to decode the data. The first security level is related to the constant optical power in the transmission link. To further enhance the security, a low coherent source is used to send false data down the transmission link. Common mode rejection is used to separate the real signal from the false signal. This system provides a high signal-to-noise ratio as well as a low crosstalk in a wavelength division multiplexing network.