Photonic Crystal Fiber Based Entangled Photon Sources.

摘要

We generate high-purity correlated and entangled photon- pairs at the telecom wavelengths in a cooled 10-meter highly nonlinear fiber (HNLF). In our previous project (contract no: FA8750-12-1-0136), we were able to generate correlated/entangled photon-pair using the highly nonlinear fiber in a counter-propagating scheme (CPS). With the HNLF at room temperature, we obtain coincidence-to-accidental ratio (CAR) approximately 26-30 and two-photon interference with visibility approximately 92%-93%. This is the best performance compared to the reported results in the literature on HNLF and Photonic Crystal Fiber (PCF) at telecom wavelengths. Unlike the PCF or microstructure fiber, the HNLF can be cooled at liquid nitrogen temperatures (77K) to suppress Raman photons. By cooling the HNLF, we expect to obtain a CAR approximately 130 and two-photon interference with visibility > 98%. We will verify the non-local behavior of high-purity HNLF-based entangled photon-pairs by making Bell's Inequalities measurements. We investigate the effect of multiple scattering on the telecom wavelength photon-pair. Our findings show that quantum correlation of polarization-entangled photon-pairs is better preserved than polarization-correlated photon-pairs in multiple scattering processes.