A method for generating multichannel entangled photon pairs

摘要

A method is presented for generating multiple-channel color-entangled photon pairs simultaneously based on type Ⅰ quasi-phase-matched spontaneous parametric downconversion pumped in a single periodically poled lithium niobate (PPLN) crystal. It is predicted that one-, and two-channel color-entangled photon pairs can be simultaneously generated just by suitably choosing the PPLN grating period and the pump frequency. We point out that the full width at half maximum (FWHM) of idler and signal light are broadened dramatically due to spontaneous parametric downconversion in case of a pulsed pump. Then this method is applied for generating multiple-channel polarization-entangled photon pairs simultaneously based on type Ⅱ quasi-phase-matched spontaneous parametric downconversion.