Study On Generation Of Entangled Photon Pairs Through Photonic Crystal Fiber

This dissertation covers the study of entangled photon-pairs generation in photonic crystal fiber(PCF). As PCF has several advantages such as adjustability of zero-dispersion wavelength in a large region and high nonlinear coefficient, we use it to generate correlated photon-pairs instead of conventional fiber or nonlinear crystal.Entangled photon pairs are the critical resources in quantum key distribution (QKD) system. Four-wave-mixing (FWM) in optical fiber is a promising candidate for a quantum correlated photon-pairs source, because photons generated from such sources can be coupled into transmission fiber very efficiently. For long-distance QKD system over optical fiber networks, a photon-pair source for the 1.55-μm band is especially important.The research works in the dissertation are summarized as follows:●Based the model of wavelength conversion, which is depend on the coupled-wave equation and its analytical solutions in four-wave:mixing process, we analyses the effect of several parameters, such as the photonic crystal fiber's length, nonlinear coefficient, dispersion slope and the pump power, on the experimental results. Such work has instructive significance on the selection of equipment in our experiment.●We demonstrate a high quality and high counting rate source of correlated photon pairs through four-wave-mixing (FWM) by pumping a 40m dispersion-flattened photonic crystal fiber (PCF). Using 1550nm pump pulses, we detected correlated signal (1545nm) and idler (1555nm) photons at a rate of 1.43 kHz with a coincidence/accidental coincidence (C/A) contrast of 8. Such a system can be used as the source of quantum key distribution system with a bit error rate less than 6%.