Optical secure communications with chaotic erbium-doped fiber lasers

Secure communication systems based on the chaos in erbium-doped fiber lasers are proposed and studied with two schemes: message masking and chaos shift keying. The effect of the parameter mismatch between the transmitter and the receiver on synchronization of chaos is also studied. The synchronization is maintained quite well with mismatches of parameters of 5% or even more by use of a comatching method.