安全性低和较高的峰均功率比(PAPR)是正交频分复用无源光网络(OFDM-PON)系统所面临的主要挑战,为此提出一种基于二维混沌加密的选择性映射(SLM)方案。该方案利用二维Logistic映射分别产生随机交织器和相位序列对OFDM信号进行加扰,达到系统加密的同时降低PAPR的目的。仿真结果显示,与传统SLM算法和原始光OFDM(O-OFDM)信号相比,所提出的方案可分别获得0.5 dB和3.8 dB的PAPR抑制增益。实验证明,7 Gbit/s 16QAM (Quadrature Amplitude Modulation) O-OFDM 加密信号可通过25 km标准单模光纤在强度调制/直接检测OFDM-PON系统中安全传输并且系统误码率性能得到改善。

Low security and high peak-to-average power ratio (PAPR) are two major challenges for orthogonal frequency division multiplexing passive optical network (OFDM-PON) systems. This study proposes a secure selective mapping (SLM) scheme based on two-dimensional chaotic encryption. The subcarriers of OFDM signals are scrambled by the random interleavers and phase sequences generated using a two-dimensional logistic map to achieve both encryption and PAPR reduction. The simulation results show that compared with the conventional SLM and original optical OFDM (O-OFDM) signals, the proposed scheme can obtain PAPR suppression gains of 0.5 dB and 3.8 dB, respectively. The experimental results demonstrate that a 7 Gbit/s 16-quadrature-amplitude-modulation (16QAM) O-OFDM encrypted signal can be securely transmitted in the intensity modulation/direct detection OFDM-PON system through a 25-km standard single-mode fiber. Moreover, the bit error rate performance of OFDM-PON systems is considerably improved.