On the security weaknesses of a power splitting-based passive optical network

We investigate and experimentally demonstrate the impact of continuous wave (CW) injection from a malicious ONU on the upstream transmission in a power splitting-based PON. Both OOK signal as used in a TDM-PON and OFDM signal in an OFDM-PON are considered. In our experiment, 10-Gb/s NRZ-PRBS and OFDM signals were used to test the effect of CW injection in TDM-PON and OFDM-PON, respectively. A bit error rate floor is observed for the upstream OOK signal when the signal-to-crosstalk ratio is reduced to 7.7 dB. Similarly, the CW injection from a malicious ONU also impose severe power penalty to the upstream OFDM signal. To overcome this security issue, we propose a novel protection scheme via harvesting the optical energy at the remote node (RN) that is originally wasted in a common power splitting-based PON. The proposed protection scheme can maintain the passive nature of the RN.