Chaos-Based Communications at High Bit Rates Using Commercial Fibre-Optic Links

Chaotic signals have been proposed as broadband information
carriers with the potential of providing a high level of robustness
and privacy in data transmission1,2. Laboratory demonstrations of
chaos-based optical communications have already shown the
potential of this technology3–5, but a field experiment using
commercial optical networks has not been undertaken so far.
Here we demonstrate high-speed long-distance communication
based on chaos synchronization over a commercial fibre-optic
channel. An optical carrier wave generated by a chaotic laser is
used to encode a message for transmission over 120km of optical
fibre in the metropolitan area network of Athens, Greece. The
message is decoded using an appropriate second laser which, by
synchronizing with the chaotic carrier, allows for the separation of
the carrier and the message. Transmission rates in the gigabit per
second range are achieved, with corresponding bit-error rates
below 1027. The system uses matched pairs of semiconductor
lasers as chaotic emitters and receivers, and off-the-shelf fibre-optic
telecommunication components. Our results show that information
can be transmitted at high bit rates using deterministic
chaos in a manner that is robust to perturbations and channel
disturbances unavoidable under real-world conditions.