High-Speed Optical Secure Communication System Using Phase Modulated Random Noise

We report on a 10Gb/s secret transmission of an intensity-modulated message over 100km standard single mode fiber. The intensity-modulated message is encrypted with a phase-modulated random noise. Without decryption, the transmission signal appears to be noise-like and cannot be recovered with post-processing method. With decryption, bit error rate below 10–8 is obtained. Decryption degradations with the mismatch of different hardware parameters are researched, This scheme provides a large key space with delay time the sensitive secret key and a robust decryption with the robustness of other hardware parameters.