A 2-D photonic crystal based source of polarization entangled photon pairs with high nonlinear conversion efficiency and without walk-off compensation

Spontaneous parametric down-conversion in 2-dimensional photonic crystal made of semiconductor material with large nonlinear susceptibility is proposed to generate entangled photon pairs with high nonlinear conversion efficiency. In particular, the walk-off between the down-converted photons with orthogonal polarization states can be minimized through appropriate structure parameter design, leading to elimination of compensation measures to mitigate labeling effect on polarization entangled photon pairs.