We report the generation of near-IR nondegenerate correlated photon pairs in a 13- cm-long optical nano-fiber. The coincidence-to-accidental ratio (CAR), 400 has been achieved at average pump power of 70 μW.
We study the generation of correlated photon pairs via spontaneous four-wave mixing (SFWM) in a 15 cm long micro/nano-fiber (MNF). The MNF is properly fabricated to satisfy the phase-matching condition for generating the signal and idler photon pairs at wavelengths of about 1310 and 851 nm, respectively. Photon-counting measurements yield a coincidence-to-accidental ratio of 530 for a photon production rate of about 0.002 (0.0005) per pulse in the signal (idler) band. We also analyze the spectral information of the signal photons originating from SFWM and Raman scattering (RS). In addition to discovering some unique features of RS, we find the bandwidth of the individual signal photons is much greater than the calculated value for the MNF with homogeneous structure. Our investigations indicate the MNF is a promising candidate for developing the sources of nonclassical light and the spectral property of photon pairs can be used to noninvasively test the diameter and homogeneity of the MNF.
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.
We demonstrate an all-fiber photon-pair source with the highest coincidence-to-accidental ratio (CAR) reported to date in the fiber-optic telecom C-band. We achieve this through careful optimization of pairproduction efficiency as well as careful characterization and minimization of all sources of background photons, including Raman generation in the nonlinear fiber, Raman generation in the single-mode fiber, and leakage of pump photons. We cool the nonlinear fiber to 4 K to eliminate most of the Raman scattering, and we reduce other noise photon counts through careful system design. This yields a CAR of 1300 at a pair generation rate of 2 kHz. This CAR is a factor of 12 higher than previously reported results in the C-band. Measured data agree well with theoretical predictions.