Figure 3

(Color online) Optimal phase sensitivity via product detection as a function of (a) g and (b) \(N_{a}\) with one coherent input state. The blue line represents the HL, the dashed purple line represents the shot noise limit (SNL), the dot-dashed red line represents the quantum Cramér–Rao bound (QCRB), the dotted green line represents the phase sensitivity via product detection in the ideal case, the dashed red line represents the phase sensitivity via product detection with photon loss \(L=0.05\), and the dashed brown line represents the phase sensitivity via product detection with photon loss \(L=0.10\)