Enhanced Secure Strategy for OFDM-PON System by Using Hyperchaotic System and Fractional Fourier Transformation

We propose and experimentally demonstrate a scheme whereby hyperchaos and fractional Fourier transform (FrFT) techniques are integrated in an orthogonal frequency-division multiplexing (OFDM) passive optical network system. In our experiment, both security issues and transmission performance are investigated under an overall frame, and 7.64-Gb/s 16-quadrature-amplitude-modulation OFDM data with a four-level encryption scheme are successfully transmitted over a 25-km standard single-mode fiber. The results show that the system security and the transmission performance can be improved simultaneously. Moreover, the proposed scheme allows a flexible adjustment between the safety and the transmission performance according to the actual requirements.