Based on the spontaneous four wave mixing in micro/nano-fiber (MNF), we report the generation of quantum-correlated
photon pairs. The wavelengths of the signal and idler photons are in the 1310 nm and 851 nm bands, respectively. The
measured ratio between the coincidence and accidental coincidence rates of signal and idler photons is up to 530.
Moreover, we characterize the spectral property of the signal photons in the wavelength range of 1270-1610 nm. The
results reveal that the bandwidth of the photon pairs is much greater than the theoretically expected value due to the
inhomogeneity of the MNF; while the spectrum of Raman scattering in MNF is different from that in conventional
optical fibers and photonic crystal fibers, which may originate from the heating used for fabricating the MNF. Our
investigation shows that the MNF is a promising candidate for developing the sources of quantum light in micro- or
nanometer-scales, and the spectral property of photon pairs can be used to non-invasively test the diameter and
homogeneity of the MNF.
Based on the dispersion property of a given photonic crystal fiber (PCF), we study how to directly generate
frequency de-correlated photon pairs via pulse pumped spontaneous four wave mixing from both the theoretical
and experimental aspects. The numerical investigation shows that to generated the frequency de-correlated
photon pairs, the experimental parameters should be properly optimized by balancing the influences of the
high order dispersion and the intrinsic sinc oscillation of phase matching function, apart from the satisfaction of
specified phase matching condition and the usage of transform limited pump pulses. We also conduct experiment
to verify the numerical simulations, and the experimental results qualitatively agree with the calculations. For
the filter free case, the experimentally obtained maximum g<sup>(2)</sup> of the individual signal photons is 1.76 ± 0.02.
When this kind of photon pairs is used to realize the heralded single photons, the heralding efficiency can reach