Power-penalty-free all-optical decryption using stimulated Brillouin scattering in optical fiber

We propose to all-optically encrypt and decrypt high-speed optical signals using the stimulated Brillouin scattering (SBS) effect in optical fiber for the first time. The spectral-shaped SBS gain or loss distorts the broadband optical signal so as to realize optical encryption. A corresponding SBS loss or gain with the same spectral shape and amplitude recovers the distorted signal to implement optical decryption. We experimentally demonstrate the SBS encryption/decryption process on 10.86 Gb s^-1 non-return-to-zero-on- off-keying (NRZ-OOK) data using phase-modulated Brillouin pumps to generate a spectral-shaped SBS gain/loss encryption key, and no power penalty is observed for the best decryption case. The proposed all-optical encryption/decryption method is completely compatible with existing fiber-optic communication systems.