Fig. 5: The data, schematic, and experimental setup involved in sections “Discussion” and “Methods”.
From: High-performance quantum entanglement generation via cascaded second-order nonlinear processes
a A comparison of the CAR values and the detected photon-pair rate among the photon-pair sources in previous literature and our work. Ref. 80 is visible-telecom source, and others are all-telecom sources. The sources based on SFWM, SPDC, and cascaded SHG/SPDC processes are represented by triangles, rectangles and circles, respectively. b A scheme of a fully integrated structure for generating high-performance correlated/entangled photon-pairs by using cascaded SHG and SPDC processes. A inner waveguide is inserted between the SHG and SPDC regions to remove the residual pump light at 1.5 μm. c Setup for the spectra measurement of SpRS noise photons and correlated photon-pairs. The PBS used in this setup is a cube, rather than a fiber-coupled one, in order to avoid the dependence of splitting ratio on wavelength. d, e The pump power dependence of the noise photons at signal and idler wavelengths, respectively. All the error bars are estimated by Poissonian photon-counting statistics. f A set of typical histograms of two-fold and three-fold coincidence counts obtained in the quantum-state tomography of time-bin entanglement.
