  In this work we show a strategy for synchronization of three optoelectronic
oscillators (OEO) operating in chaotic regime. Two applications of synchronized
OEOs in secure communications are considered. In the first one the OEO is used
to produce a pseudo-random bit sequence. The second application is an optical
setup for secure transmission of sampled analog signals. Using numerical
simulations, we calculated the bit error rate taking into account parameter
mismatch noise and Gaussian noise in the input optical power. The conditions
for error rate of up to 15% during key generation are shown.
