Fig. 1. Entangled equivalent scheme of SR-CV-QKD protocol with optical amplifier

Fig. 2. Structural models of two types of amplifiers. (a) PIA; (b) PSA

Fig. 3. Asymptotic secret key rate of homodyne detection combined with PSA under asymptotic case

Fig. 4. Secret key rate of heterodyne detection combined with PIA under asymptotic case

Fig. 5. Maximum transmission distance under different amplifier noise

Fig. 6. Secret key rate of homodyne detection combined with PSA under finite code length