1.562 Gb/s phase-encrypted secure communication

A field programmable gate array (FPGA)-based physical layer phase-encryption technique suitable for applications in high-speed passive optical networks is presented. The physical layer ciphering technique is based on a combination of multilevel phase shift keying (PSK) modulation and binary differential PSK. A mathematical model of the system is first derived and numerical simulations are obtained using Mathematica. Expressions for the probability of error for both a legitimate and eavesdropping receiver are derived and evaluated numerically. The results from experimental implementation using high-speed phase modulators and FPGAs are also given to further prove the efficacy of the presented technique. The macroscopic cryptography technique offers completely opaque communication over trans-oceanic distances, gigabit date rates and multiple wavelengths.