Phase chaos generation and security enhancement by introducing fine-controllable dispersion

For the first time, we experimentally demonstrate phase chaos generation by introducing a fine-controllable dispersion module into the feedback-delayed loop. To study the effect of this specific nonlinearity, we demonstrate the nonlinear dynamics evolution route in terms of the dependence of dispersion and feedback gain parameters by both experiment and simulation, which show good agreement. We also investigate the synchronization error variation with the dispersion mismatch to evaluate the security level of the proposed phase chaos system. The results show that the proposed approach can simultaneously simplify the phase chaos synchronization and enhance the key space, which has potential to be used in high-speed chaotic optical communications.