214Intensity-Level 10-Gbaud Y-00 Quantum Stream Cipher Enabled by Coarse-to-Fine Modulation

For secure fiber-optic transmission, we demonstrate a 10-Gbaud Y-00 quantum stream cipher that achieves quantum noise masking using 2
¹⁴
(=16,384) intensity-level modulation. Coarse-to-fine driving of a dual-drive Mach-Zehnder modulator using two synchronized digital-to-analog converters is employed for the modulation. Successful off-line decryption of the cipher is achieved.