Research on co-propagation of QKD and classical communication by reducing the classical optical power

He Ru-Shi^{1, 2}, Jiang Mu-Sheng^{1, 2, †}, Wang Yang^{1, 2}, Gan Ya-Hui^{1, 2}, Zhou Chun^{1, 2}, Bao Wan-Su^{1, 2, ‡}

Simulated QKD secure key rates with quantum signals co-propagating with classical channel, using Eq. (5). The minimum classical optical power is the experimental data obtained by measuring the classical optical power and detector sensitivity according to Section 2. Combined with the formulas (1) and (2), that is, the function of Raman scattering and classical optical power, the crosstalk noise can be calculated. Only SpRS is considered. The line in the figure represents OOK, PPM, and no multiplexing from left to right.