QKD time correlation light source side channel suppression method and transmitting end thereof

According to the QKD time correlation light source side channel suppression method and the sending end thereof, the extinction ratio of a laser light source is improved by simply adjusting parameters of the laser light source, or parameters (such as the shape of a phase modulation signal and/or the arrival time difference of two pulse components relative to a phase modulator) of a polarization coding module are adjusted; according to the method, the correlation between the weak light polarization state and the polarization coding information between the light pulses is weakened, a time correlation light source side channel is suppressed, the method does not need to depend on the manufacturing process of an intensity modulator, the safety limitation caused by imperfect devices can be well overcome, and therefore the safety of the QKD process is greatly improved in a simple mode and at low cost. 本发明提出了一种QKD时间相关性光源侧信道抑制方法及其发送端，其中，通过简单地调整激光光源的参数提高其消光比或者调整偏振编码模块的参数(例如相位调制信号的形状和/或两个脉冲分量关于相位调制器的到达时间差)，减弱光脉冲间弱光偏振态与偏振