Phase sensitivity of two nonlinear interferometers with inputting entangled coherent states
Chao-Ping Wei, Hu Xiao-Yu, Yu Ya-Fei, Zhang Zhi-Ming†,
       

(a) The phase sensitivity against the gain factor g for a given |α| = 3, and θα = π/2. (b) The phase sensitivity against the amplitude |α| for a given g = 2 and θα = π/2. (c) The phase sensitivity against the total average photon number N. Black solid line: SU(1,1)I; blue dot-dashed line: MMZI; red dotted line: the shot-noise limit orange dashed line: the Heisenberg limit(1/NT); green solid line: the linear MZI.