Constellation Shaping Chaotic Encryption Scheme with Controllable Statistical Distribution for OFDM-PON

Abstract In order to improve the signal transmission performance and physical layer security in orthogonal frequency division multiplexing passive optical network (OFDM-PON), we propose a constellation shaping chaotic encryption (CSCEn) scheme with controllable statistical distribution in this paper. In this scheme, a quadrature amplitude modulation (QAM) symbol sequence is divided into several sub-sequences, and a further probabilistic shaping (PS) is performed by constellation region replacement in terms of the corresponding statistical information (SI). Then the sequence SI is encoded and encrypted into chaotic signal phases by employing our key distribution algorithm. At the receiver, the SI is extracted first to restore the original signal. To verify the effectiveness of this scheme, we successfully demonstrate an encrypted PS-16-QAM signal transmission over a 25-km standard single mode fiber (SSMF). The results show that the proposed scheme can flexibly improve bit error rate (BER) performance with low implementation complexity and provide sufficient security to resist attacks from illegal optical network units (ONUs), thus displays a promising application prospect for future secure PON. Index Terms Probabilistic shaping, chaotic encryption, key distribution, OFDM-PON, physical layer security.