The symmetric and antisymmetric phase modulation for the joint spectral amplitude of the biphotons in SPDC

Abstract

We analysis the generation of entangled biphotons by symmetric and antisymmetric phase modulation to obtain the corresponding joint spectral amplitude functions (JSAF) during the spontaneous parametric down-conversion (SPDC). With the help of Schmidt decomposition, the distribution probabilities of different modes are analyzed and the degree of entanglement is improved, which in turn leads to the effective regulation of entanglement, entropy, Schmidt coefficient and Schmidt number. Through simulations, we find that the antisymmetric phase modulation can slightly broaden the spectrum width, and the symmetric phase modulation distribution is more advantageous when the crystal is shorter.