Chip-integrated photon-pair sources based on spontaneous parametric down-conversion (SPDC) have emerged as a promising solution for scalable quantum light generation. Thin-film lithium tantalate (TFLT) is a compelling
χ(2) platform, combining strong nonlinearity with a high optical-damage threshold, weak photorefractive response, and ferroelectricity that enables quasi-phase matching. However, SPDC-based photon-pair generation on TFLT has not yet been demonstrated. Here, we combine high-quality periodic poling with low-loss nanophotonic waveguides to realize photon-pair sources on TFLT in both traveling-wave and resonant configurations. In periodically poled straight waveguides, we achieve broadband photon-pair generation with high efficiency (
2.1 GHz mW−1) and coincidence-to-accidental ratio (up to
3.8×105). We further confirm high-purity single-photon operation via heralded second-order correlation (
gH(2)(0)=0.0018±0.0002) and high-fidelity time-energy entanglement through Franson interference (visibility of
98.9±0.5%). In periodically poled racetrack resonators, we map out a broad quantum frequency comb spanning the telecom C- and L-bands. By isolating individual frequency-correlated pairs, we measure a high spectral brightness of
11 GHz mW−1 GHz−1. These results are competitive with the state of the art across
χ(2) integrated platforms, positioning TFLT as a strong contender for integrated quantum light sources, with applications in wavelength-multiplexed quantum communications and photonic quantum information processing.
Abstract Chip-integrated photon-pair sources based on spontaneous parametric down-conversion (SPDC) have emerged as a promising solution for scalable quantum light generation. Thin-film lithium tantalate (TFLT) is a compelling
χ(2) platform, combining strong nonlinearity with a high optical-damage threshold, weak photorefractive response, and ferroelectricity that enables quasi-phase matching. However, SPDC-based photon-pair generation on TFLT has not yet been demonstrated. Here, we combine high-quality periodic poling with low-loss nanophotonic waveguides to realize photon-pair sources on TFLT in both traveling-wave and resonant configurations. In periodically poled straight waveguides, we achieve broadband photon-pair generation with high efficiency (2.1~GHz~mW
−1) and coincidence-to-accidental ratio (up to
3.8×105). We further confirm high-purity single-photon operation via heralded second-order correlation (
gH(2)(0)=0.0018±0.0002) and high-fidelity time-energy entanglement through Franson interference (visibility of
98.9±0.5%). In periodically poled racetrack resonators, we map out a broad quantum frequency comb spanning the telecom C- and L-bands. By isolating individual frequency-correlated pairs, we measure a high spectral brightness of 11~GHz~mW
−1~GHz
−1. These results are competitive with the state of the art across
χ(2) integrated platforms, positioning TFLT as a strong contender for integrated quantum light sources, with applications in wavelength-multiplexed quantum communications and photonic quantum information processing.
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.
on a coarse wavelength-division-multiplexing grid that spans 140 nm by using a 300-μm-long poled region in a thin-film periodically-poled lithium-niobate ridge waveguide bonded to silicon. The pairs are generated via spontaneous parametric downconversion pumped by a continuous-wave tunable laser source. The small mode area of the waveguide allows for efficient interaction in a short length of the waveguide and, as a result, permits photon-pair generation over a broad range of signal-idler wavelengths.