Second order dispersion in the interferometer's optical elements for quantum cryptography (QC)‎ system

الملخص EN

In this study, we have studied the entangled photon source and how the coincident count rate and visibility could be affected by the optical elements of the system setup.

The profile 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 to increase of visibility.

Non zero chirp parameter (ai) of the pump beam can provide a higher central peak but on the other hand it reduces the visibility, the peak remains, while the dispersion in an optical element through which down converted photon propagate leads to asymmetry in the interference pattern dip, the dip is particularly stretched with larger value of birefringent material length (20-30) mm.

The highest visibility at birefringent material dispersion (d) equals to zero, and the dip was broader at larger value of (d).