Fig. 1. Principle diagram of conventional SLM method

Fig. 2. Principle diagram of SLM scheme based on two-dimensional chaotic encryption in IM/DD OFDM-PON systems

Fig. 3. CCDF curves for different values of V and U

Fig. 4. Properties of chaotic sequences. (a) Auto-correlation of chaotic sequences; (b) cross-correlation of chaotic sequences; (c) chaotic sequences under tiny change of initial value

Fig. 5. CCDF curves for different phase sequences

Fig. 6. PAPR comparison of proposed and other schemes

Fig. 7. Experimental setup of IM/DD OFDM-PON encryption system

Fig. 8. Comparison of bit error rate performance