The Phase Sensitivities for Different Phase-Shift Configurations in an SU(1,1) Interferometer*

Fan Wang,Wei Zhong,Lan Zhou,Yu-Bo Sheng

Fig. 3 (Color online) (a) Difference between the sensitivities of the two types of phase shift: $\Delta\theta_{{QCRB}}^{{A}}\sqrt{N_{{ t}}}-\Delta\theta_{{QCRB}}^{{B}}\sqrt{N_{{ t}}}$. The green dashed line represents the amount of QFIs in two cases is equal. (b) Phase sensitivity $\Delta\theta_{{QCRB}}\sqrt{N_{{ t}}}$ as a function of coherent amplitude $|\alpha|$ for $r=0$. The blue line is phase shift in one arm, the red line is phase shift in both arms. The gain factor of OPA$_{1}$ is $s_{1}=1$.