Long-Haul Optical Chaos Synchronization Employing Optical Phase Conjugation

For long-haul optical chaos communication and secure key distribution, a primary challenge is establishing the chaos synchronization between the transmitter and receiver. However, the chaos synchronization distance demonstrated in many literatures is restricted within only a few hundred kilometers due to the impairments arising from fiber dispersion and nonlinearity. Here, we propose and demonstrate a scheme of long-haul chaos synchronization employing optical phase conjugation (OPC). Thanks to the OPC compensating the fiber dispersion and nonlinearity, thousand-kilometer-level chaos synchronization is achieved in simulations. Optimization of launching power, fiber transmission-distance, linewidth of the pump laser in the OPC module are well studied. Finally, an up to 2240-km chaos synchronization with a synchronization coefficient beyond 0.9 is obtained.