Digital Coherent PSK Y-00 Quantum Stream Cipher for Secure Optical Fiber Communications

Ken Tanizawa, Fumio Futami

) in the transmissions over the 400-km SSMF.

Masataka Nakazawa, Masato Yoshida, Toshihiko Hirooka +1 more

马乐 Ma Le, 张杰 Zhang Jie, 王博 Wang Bo +6 more

Ken Tanizawa, Fumio Futami

We present a symmetric-key direct data encryption technique utilizing signal masking by quantum noise, called Y-00 quantum stream cipher. Physical encryption of phase-shift-keying (PSK) Y-00 quantum stream cipher is achieved by our proposed extremely high-order phase modulation. Two cascaded phase modulators are driven with two synchronized digital-to-analog converters for coarse-to-fine modulations, resulting in a record 217 phase levels for the quantum noise masking. Decryption of the cipher is implemented in digital signal processing after intra-dyne coherent detection with a free-running local oscillator. We experimentally demonstrate transmission of 10-Gbaud digital-coherent PSK Y-00 cipher with 217 levels over a 240-km field-installed single-mode fiber.

Fumio Futami

Ken Tanizawa, Fumio Futami

We present the first experimental demonstration of digital-coherent PSK Y-00 quantum stream cipher employing noise masking for secure communications. Successful demodulation with decryption in digital domain is achieved for 10-Gbit/s Y-00 cipher with 1024 bases.