Chaotic Arnold transform and chirp matrix encryption scheme for enhancing the performance and security of OFDM-PON

In this paper, we first propose and experimentally demonstrate an encryption scheme by combining the chaotic Arnold transform (CAT) and chaotic chirp matrix (CCM) techniques in orthogonal frequency division multiplexing passive optical network (OFDM-PON) system to simultaneously enhance physical-layer security and system transmission performance. In this system, the CAT is employed to scramble quadrature amplitude modulation (QAM) symbols in the time-frequency domain, thereby obtaining data encryption. Moreover, the CCM is designed to reduce the peak-to-average power ratio (PAPR) of OFDM signals and further enhance the system security. With these processing techniques, similar to 10(712) key space can be created to protect against exhaustive trials. A 10-Gb/s encrypted 16-QAM-based OFDM signal transmission is successfully demonstrated over a 20-km single mode fiber (SMF) by experiment. The results show that, our proposed method can achieve similar to 2-dB PAPR reduction and similar to 1.2-dB sensitivity improvement compared with the common OFDM-based PON system. Therefore, it can be considered a promising candidate for physical security enhancement in future OFDM-PON.