Thin-film lithium tantalate (TFLT) has emerged as a promising integrated photonic platform owing to its low photorefractive noise, high optical damage threshold, and reduced birefringence, attracting increasing interest for scalable photonic technologies. Here, to the best of our knowledge, we demonstrate the first quantum light source with TFLT via spontaneous four-wave mixing, bridging the gap between the rapidly advancing classical TFLT ecosystem and integrated quantum photonics. The fabricated microring exhibits a free spectral range of 350~GHz and an optical quality factor of
106, enabling efficient cavity-enhanced nonlinear interactions. Correlated photon pairs are generated across the telecom band from 1510 to 1570~nm, with a photon pair generation rate of 24
MHz/mW2 at a wavelength of 1535.04 nm. The source delivers strongly antibunched heralded single photons with
gH(2)(0)=0.071±0.004 at a heralding rate of 170 kHz, while the unheralded statistics yield
g(2)(0)=1.93±0.05, indicating near-single-temporal-mode emission. Energy-time entanglement is further confirmed by a raw two-photon interference visibility of
92.55±0.94%, well above the Bell-inequality violation threshold. These results establish TFLT as a manufacturing-compatible platform for scalable photonic quantum circuits, paving the way for the monolithic co-integration of classical and quantum photonic functionalities.
We report the design of an integrated photon pair source based on spontaneous four-wave mixing (SFWM), implemented in an integrated micro-ring resonator in the silicon nitride platform (Si 3 N 4 ). The signal photon is generated with emission at 606 nm and bandwidth of 3.98 MHz, matching the spectral properties of praseodymium ions (Pr), while the idler photon is generated at 1430.5 nm matching the wavelength of a CWDM channel in the E-band. This novel, to the best of our knowledge, device is designed to interact with a quantum memory based on a Y 2 SiO 5 crystal doped with Pr 3+ ions, in which we used cavity-enhanced SFWM along with dispersion engineering to reach the required wavelength and the few megahertz signal photon spectral bandwidth.
Silicon micro-ring resonators have been demonstrated to be potential “on- chip” efficient sources of time-energy entangled photons. In these devices, photon pairs are generated by spontaneous four-wave-mixing (SFWM), an elastic scattering event involving two pump photons that results in the generation of an idler and a signal photon. The mass production of such integrated devices for quantum optic experiment requires the implementation of fast and reliable techniques to monitor the emitted two-photon state as well as the device performances. In this work we show that the joint spectral density of photon pairs that would be generated by SFWM in a silicon ring resonator can be measured with unprecedented resolution and speed, improving of several orders of magnitudes the results of traditional approaches based on coincidence measurements.
Recently, many researchers focus on the integration of single photon sources on an optical chip toward the realization of large-scale quantum information processing.Identical single photons are required to obtain good interference between photons for quantum information processing, for which high "spectral purity" of single photons is required.An appealing scheme is employing the spontaneous four-wave mixing (SFWM) in a silicon micro-ring resonator (MRR) because it allows us to generate high-purity photons without external spectral filters.However, the purity value is limited to 0.92 due to the dispersion property of an MRR We have developed a new scheme to further increase the spectral purity from an MRR by manipulating the spectral phase distribution of the pump pulse.Via exploring several strategies on the spectral phase modulation, we found that the purity of single photon can be increased up to approximately 0.96 breaking the conventional limitation of 0.92 in a standard MRR.We further explore the experimental feasibility of the scheme toward future implementation.
Photon sources are fundamental components for any quantum photonic technology. The ability to generate high count-rate and low-noise correlated photon pairs via spontaneous parametric down-conversion using bulk crystals has been the cornerstone of modern quantum optics. However, future practical quantum technologies will require a scalable integration approach, and waveguide-based photon sources with high-count rate and low-noise characteristics will be an essential part of chip-based quantum technologies. Here, we demonstrate photon pair generation through spontaneous four-wave mixing in a silicon micro-ring resonator, reporting separately a maximum coincidence-to-accidental (CAR) ratio of 602 ± 37 (for a generation rate of 827kHz), and a maximum photon pair generation rate of 123 MHz ± 11 kHz (with a CAR value of 37). To overcome free-carrier related performance degradations we have investigated reverse biased p-i-n structures, demonstrating an improvement in the pair generation rate by a factor of up to 2 with negligible impact on CAR.