Chaotic signal scrambling for physical layer security in OFDM-PON

We propose and demonstrate physical layer security schemes via implementation of chaotic signal scrambling such as partial transmit sequence (PTS) and selected mapping (SLM) techniques in orthogonal frequency-division multiplexing passive optical network (OFDM-PON). The digital chaotic sequences are employed in PTS/SLM schemes to encrypt the OFDM data, which provides a huge key space to enhance the physical layer confidentiality. Transmission of 8.9Gb/s 16QAM encrypted OFDM signals is demonstrated over 20km standard single-mode fiber, which shows the security enhancement against malicious eavesdropping or exhaustive attacks. Moreover, the proposed secure schemes improve the OFDM transmission performance since the peak-to-average power ratio (PAPR) of the OFDM signals is significantly reduced by the signal scrambling.