Quantum scientists give Triplex® a HUG to entangle single photons
Data security faces unprecedented challenges with the emergence of quantum computers and artificial intelligence. For more secure encryption, Quantum Key Distribution (QKD) protocols, that rely on quantum entanglement principles, stand out as solutions. Using TriPleX® silicon nitride, a group of researchers at the University of Padova conducted a Bell test on energy-time entangled photons. The test used a TriPleX® photonic integrated circuit (PIC) to address the post-selection loophole, important for information security in quantum key distribution. The group, led by Giuseppe Vallone, demonstrated Bell inequality violation on time-bin entanglement via the “HUG” interferometric configuration, enabled by the ultra-low losses of our photonic integration technology.
The “HUG” interferometric configuration on a silicon nitride chip
Quantum entanglement is a phenomenon where the quantum states of two or more particles become correlated in such a way that the state of one particle cannot be described independently of the state of the other, regardless of the distance between them. Time-bin and energy-time entanglement are specific types of entanglement that are particularly important for long-distance quantum information processing. Time-bin entanglement involves entangling particles based on their arrival times at different locations, while energy-time entanglement is based on the energy levels and arrival times of the particles. However, traditional implementations of time-bin and energy-time entanglement suffer from a fundamental flaw known as the post-selection loophole.
A group of researchers at the University of Padova have demonstrated post-selection loophole-free certification of time-bin or energy-time entanglement on a photonic integrated circuit (PIC), using silicon nitride chips fabricated by LioniX International. They accomplished this feat by implementing a scheme known as the “HUG” on a TriPleX® silicon nitride chip. The HUG encryption method uses entangled single photons are shared between two communication parties and measured through an interferometer. To increase the allowable distance between the parties to practical ranges, they entangled the photons in time bins and energy-time.
Beam-splitter
Spontaneous parametric down-conversion
Dichroic mirror
Half-wave plate
Manual polarization controllers
Polarizing beam-splitter
Photonic integrated chip
Superconducting nanowire single-photon detectors
Overview scheme of the experimental setup used to generate time-bin entangled states and certify their entanglement
The “HUG” interferometer scheme, like any single-photon interferometer, demands low loss and stable path lengths. The ultra-low propagation and fiber coupling losses of the TriPleX® chips allowed the scientists to achieve great accuracy in their Bell tests, adding. The accuracy of their measurements put 10 standard deviations of exclusion of the hidden variables theory, which is the alternative to explain entanglement in quantum theory. With the new encoding , the highly scalable TriPleX® silicon nitride platform can enable long range data security for QKD systems.
Experiment with photonic integrated circuits with our MPW run
The scientists used for this experiment standard, reliable building blocks in our PDK. The low-losses can be made even lower with our custom design and fabrication capabilities, providing further optimizations to coupling efficiency and heater stability. The scalability of the device could be further improved via the integration of other optical components, such as single-photon sources and detectors. The achievement of the researchers marks another inspiring step in the realization of market-ready quantum processing and communications, which we are always happy to enable with our photonic integration know-how!
Dr. Philip P.J. Schrinner started his scientific career at the (RWTH) Aachen University, where he received his B.Sc and M.Sc in the field of quantum/nano technology. To further deepen his background and to research in the field of integrated optics, he proceeded with his PhD at the University of Münster (WWU). After designing, fabricating and characterizing hybrid quantum light sources in photonic integrated circuits in the university cleanroom and labs, he joined Lionix International in 2021. In addition to developing new hybrid photonic assemblies, he is now the project leader for several commercial, national and EU projects.
Take a look at:
🌐 The academic paper in Optica by scientists at University of Padova.
🌐 LioniX Multi Wafer Project (MPW) services.
🌐 Monthly updates on our developments and events via our newsletter!
More articles from LioniX International experts:
