Second Order Dispersion In The Interferometer's Optical Elements For Quantum Cryptography (QC) System


In this study, we have studied the entangled photon source and how the coincidentcount rate and visibility could be affected by the optical elements of the system setup. Theprofile of the interference dip of the optical elements for Quantum Cryptography (QC)system is modified by the increase of the second order dispersion parameter (Dp) and lead toincrease of visibility. Non zero chirp parameter (ai) of the pump beam can provide a highercentral peak but on the other hand it reduces the visibility, the peak remains, while thedispersion in an optical element through which down converted photon propagate leads toasymmetry in the interference pattern dip , the dip is particularly stretched with larger valueof birefringent material length (20-30)mm. The highest visibility at birefringent materialdispersion (d) equals to zero, and the dip was broader at larger value of (d).