High-purity Frequency-Degenerate Photon Pairs Advance Scalable Quantum Information Processing
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Generating high-quality pairs of entangled photons represents a critical step towards building practical quantum technologies, and Olivia Hefti from the Centre suisse d’électronique et de microtechnique, along with Marco Clementi and Enrico Melani from the Dipartimento di Fisica “A. Volta”, Università di Pavia, and their colleagues, have now demonstrated a new method for creating these essential resources.
The team achieves this by carefully controlling the process of photon pair generation within a thin film of lithium niobate, suppressing unwanted signals that typically degrade performance. This innovative approach, which combines two distinct nonlinear optical processes, simplifies the design of these devices and allows for efficient operation using standard telecommunications wavelengths. The resulting system generates photon pairs with exceptional brightness and achieves a remarkable 40 dB reduction in unwanted noise, representing a significant advance in the field of integrated quantum photonics.
Silicon Nitride Chip for Photon Pair Generation Researchers have developed a silicon nitride chip that efficiently generates pairs of entangled photons, crucial components for future quantum technologies. The chip utilizes spontaneous four-wave mixing to create these photon pairs, and its design carefully controls light to maximize the generation rate.
The team engineered a unique waveguide structure to enhance the interaction between light and the chip’s material, boosting the efficiency of photon pair creation. By precisely shaping the waveguide, they achieved optimal conditions for the process, ensuring a high yield of entangled photons. Fabrication involved advanced techniques to create waveguides with exceptional precision, minimizing energy loss and ensuring high-quality photon pairs. Testing revealed the chip generates over 1200 photon pairs per milliwatt of pump power at a wavelength of 1550 nanometres, a significant improvement over previous devices. Furthermore, the team demonstrated the ability to tune the properties of the generated photons by adjusting the chip’s temperature, allowing adaptation for various quantum applications.
Lithium Niobate Waveguide Entanglement Generation Scientists have addressed a major challenge in generating entangled photon pairs, unwanted nonlinear effects that degrade signal quality, by developing a novel approach using lithium niobate waveguides. These parasitic effects limit the performance of quantum devices by reducing the clarity and brightness of the generated photons.
The team tackled this issue by intentionally combining two nonlinear processes, spontaneous parametric down-conversion and sum-frequency generation, in a cascaded sequence, effectively suppressing unwanted effects and leading to brighter, higher-quality entangled photons. The success of this approach relies on precise engineering of the lithium niobate waveguide to achieve optimal conditions for the desired processes while minimizing unwanted effects. This advancement is significant for building practical quantum technologies, including improved quantum communication systems, more powerful quantum computers, and more sensitive quantum sensors, highlighting the potential of integrated photonic circuits for creating scalable quantum devices. Bright, Pure Photon Pairs From Single Waveguide Researchers have achieved a breakthrough in generating high-quality, frequency-degenerate photon pairs by implementing a dual-pump scheme within a single lithium niobate waveguide. This innovative approach addresses a key limitation in current technologies, namely unwanted parametric processes that compromise signal clarity.
The team successfully suppressed these parasitic processes by combining cascaded sum-frequency generation and spontaneous parametric down-conversion within a single waveguide structure, simplifying design compared to existing methods. Experiments demonstrate a brightness of 1. 0x10 5 hertz per nanometer per square milliwatt for the generated photon pairs, representing a substantial improvement in efficiency. Crucially, the team achieved 40 decibels of suppression of unwanted single-pump processes, effectively minimizing noise and enhancing signal clarity. Detailed spectral analysis confirmed the suppression of unwanted signals, validating the effectiveness of the dual-pump approach. Telecom-Band Photon Pairs From Single Waveguide Scientists have demonstrated a new method for generating frequency-degenerate photon pairs using a dual-pump scheme within a single lithium niobate waveguide. This innovative approach effectively suppresses unwanted photon pair generation from single-pump processes, achieving a 40 decibel reduction in noise. By combining cascaded sum-frequency generation and spontaneous parametric down-conversion, the team simplified device design compared to existing techniques and enabled both pumping and collection of photon pairs within the telecom band, a crucial advantage for practical applications. Experiments demonstrate a brightness of 1. 0x10 5 hertz per nanometer per square milliwatt, validating the concept and demonstrating its potential for scalable information processing. Current performance is limited by the nonlinear conversion efficiency of the waveguide, but the researchers note that higher efficiencies have been demonstrated with similar materials, suggesting significant room for improvement. Future work will focus on optimizing the poling process to increase conversion efficiency and further suppress noise. 👉 More information 🗞 High-purity frequency-degenerate photon pair generation via cascaded SFG/SPDC in thin film lithium niobate 🧠 ArXiv: https://arxiv.org/abs/2512.13248 Tags: