B. Wacogne et al., DOUBLE SECURITY LEVEL IN A TELECOMMUNICATION SYSTEM BASED ON PHASE CODING AND FALSE DATA-TRANSMISSION, Journal of lightwave technology, 14(5), 1996, pp. 665-670
A new communication system exhibiting a double security level is demon
strated. Information coding is based on relative phase changes between
consecutive time intervals of the light emitted from a highly coheren
t CW source. An imbalanced Mach-Zehnder interferometer whose time dela
y matches the intervals duration is used to decode the data. The first
security level is related to the constant optical power in the transm
ission link. To further enhance the security, a low coherent source is
used to send false data down the transmission link. Common mode rejec
tion is used to separate the real signal from the false signal. This s
ystem provides a high signal-to-noise ratio as well as a low crosstalk
in a wavelength division multiplexing network.