Effect of transmission fiber on chaos communication system based on erbium-doped fiber ring laser

We report a numerical study on the deterioration of eye opening penalty (EOP) and bit error rate (BER) of the received message from a communication system based on chaos generated in erbiumdoped fiber ring laser (EDFRL) under the influence of amplifier noise, transmission fiber dispersion, and nonlinearity. Three different transmission fibers with practical parameters are considered. We find that in order to realize high-bit-rate chaotic communication, the residual fiber dispersion should be kept as small as possible. Furthermore, if the transmission power is optimized to balance the effect of amplifier noise and fiber nonlinearity, a message with bit rate on the order of several gigabits/second can be transmitted over hundreds of kilometers with acceptable BER deterioration. A comparison between open- and closed-loop structures is also conducted. Moreover, we find that the maximum bit rate is limited by the bandwidth of the chaos determined by the nonlinearity of the fiber ring laser and the laser configuration. It is possible to optimize these parameters to provide the maximum chaos bandwidth and hence the maximum message bit rate.