A local local oscillator passive continuous variable quantum key distribution scheme with trusted phase noise model and optical amplifiers

Local local oscillator (LLO) passive continuous variable (CV) quantum key distribution (QKD) scheme can simplify the implementation of the LLO scheme and make it more cost-effective. Nevertheless, in practice, since the imperfect device employed, such as imperfect lasers and detectors, traditional LLO passive CVQKD system still exists relatively large residual phase noise. Based on this, we propose a LLO passive CVQKD scheme with a trusted phase noise (TPN) model, which considers part of partial phase reference measurement noise and phase-reference light intensity real-time monitored by receiver as trusted. The reason is that the receiver can perform local calibration for it. Results illustrate that the LLO passive CV-QKD using TPN model can effectively enhance its performance compared with that of traditional LLO passive CV-QKD. Besides, we apply phase-insensitive amplifier to realize Bob’s detector imperfection compensation and achieve further secret key rate improvement over long distances by setting a suitable amplification gain.