High-quality on-chip entangled photon source with broad tunable range based on coupling compensation

This paper introduces a tunable and high-quality photon source that utilizes evanescent-wave coupling phase matching. By adjusting the coupling gap, the signal light can be tuned from 1307 nm to 1493.9 nm, and the idler light can be tuned from 1612.8 nm to 1907 nm. Throughout the entire tuning range, the purity of the photon pairs remains above 92%. In specific tuning ranges (signal photons from 1307 nm to 1421.7 nm and idler photons from 1706.4 nm to 1907 nm), the purity exceeds 99% and the full width at half-maximum of the generated photon spectra is less than 1.85 nm. The photon source is designed using a silicon-organic hybrid waveguide, which effectively minimizes the impact of two-photon absorption and achieves a 15 dB enhancement in four-wave mixing conversion efficiency compared to a strip waveguide. This design may promote efficient and precise generation of high-quality photons at desired frequencies, offering promising potential for various applications in quantum technologies.