40Gb/s Secure Optical Communication Based on Symbol-by-Symbol Optical Phase Encryption

Achieving high speed physical layer security is a constant pursuit but critical challenge for the information society. In this paper, a novel symbol-by-symbol optical phase encryption technique relying on ultra-long, reconfigurable optical phase patterns and commercial off-the-shelf dispersive components is proposed for high speed physical layer security. A record 40Gb/s secure optical communication system with symbol overlapped, optical phase encrypted differential-phase-shift-keying modulated signal is experimentally demonstrated based on the proposed technique. Security robustness against various eavesdropper's attacks has been validated for three optical codes with a chip rate of 40Gchip/s and variable code-length of 128-chip, 512-chip and 1024-chip, respectively. The demonstrated technique exhibits the advantages of supporting high bit rate operation and advanced optical modulation formats, improving code flexibility and cardinality, which makes it very promising for future ultra-fast secure optical communication.