Source monitoring is a matter of vital importance for continuous-variable quantum key distribution (QKD), since it is the first barrier to ensure the practical security. In a practical scenario, the difficulty arises with the existence of the laser intensity fluctuation, which not only contributes to the source noise but also causes the deviation of source monitoring result. We first illustrate the effect of the relative intensity noise (RIN) on the ultimate security by explicitly showing the parameter estimation procedure, and find that the secret key rate is overestimated in this situation. To defend the continuous-variable QKD system against potential attacks utilizing this impairment to conceal itself, a source monitoring scheme is devised by adopting the seminal one-time shot-noise unit calibration approach into the monitor module. It is shown that by using the practical source monitoring scheme the impact of the RIN can be modeled and monitored in real time to circumvent an overestimated secret key rate. This scheme also lowers the system complexity thus is suitable for widespread application.

源监视对于连续可变量子密钥分发（QKD）至关重要，因为它是确保实际安全性的第一个障碍。在实际应用中，由于激光强度波动的存在而造成困难，这不仅会造成光源噪声，而且会导致光源监测结果的偏差。我们首先通过明确显示参数估计过程来说明相对强度噪声（RIN）对最终安全性的影响，然后发现在这种情况下，秘密密钥率被高估了。为了保护连续变量QKD系统免受利用这种损害掩盖自身的潜在攻击，通过在监视模块中采用开创性的一次性散粒噪声单位校准方法，设计了一种源监视方案。结果表明，通过使用实际的源监视方案，可以对RIN的影响进行实时建模和监视，以规避过高估计的秘密密钥率。该方案还降低了系统复杂度，因此适用于广泛的应用。