TY - GEN AU - Yang,Can AU - Xi,Chaoxiang AU - Jing,Jietai AU - He,Guangqiang TI - Counterpropagating path-entangled photon pair sources based on simultaneous spontaneous parametric down-conversion processes of nonlinear photonic crystal SN - 1094-4087 PY - 2018///1126 N1 - Publication Type: Journal Article UR - https://doi.org/10.1364/OE.26.027945 ER -