SiN waveguides for ultra-broadband visible-telecom photon pairs

Abstract

We propose simple rectangular cross-section, few-cm long SiN waveguide designs capable of generating ultra-broadband frequency-correlated photon pairs via SFWM, exceeding an octave in bandwidth spanning the visible-to-telecom wavelengths ( $$\sim$$ 700–1700 nm for $$\sim$$ 1- $$\upmu$$ m pump) with a spectral brightness of $$>2.5\times 10^4$$ photon pairs/s/nm/mW $$^2$$ . Such compact sources, spanning the entire telecom spectrum (across O, E, S, C, L, and U bands) on one side and covering most of the major atomic transitions used in ultracold gases and solid-state based quantum memories on the other side, could potentially be employed in large-scale multi-channel hybrid (free space + fiber) quantum networking schemes in addition to the heralding of telecom single photons by utilizing high efficiency visible detectors.