Figure 4

(a) The simulated quantum polarization state preparation efficiency and (b) the intensity map of \({atan}(|\alpha |/|\beta |))\) of quantum polarization-path states of \({\rm{\Psi }}=\alpha {(|H\rangle }_{a}|V{\rangle }_{b})+\beta {(|V\rangle }_{a}|H{\rangle }_{b}))\) in frequency domain with blue star markers denoting the signal and idler photon-pair wavelengths at 1477 nm (H-polarized mode) and 1631 nm (V-polarized mode), respectively, in which the type-II SPDC source can approach to a pure quantum polarization-path entangled state (see (d)) when working with the proposed AAC. (c,d), and (e) are the simulated density matrices for a 775-nm pumped QPM type-II SPDC photon-pair source when working with the proposed AAC for phase-matched V-polarized signals at 1480, 1631, and 1790 nm (corresponding idlers at 1627, 1477, and 1367 nm), respectively.