Quantum information scientists at the U.S. Department of Energy’s Oak Ridge National Laboratory (ORNL) have achieved a major milestone in quantum networking by developing the first device to integrate essential quantum photonic functions onto a single chip. Published in Optica Quantum, the study outlines a pioneering advance in photon-based quantum computing, where qubits—quantum bits—are encoded using particles of light. These photonic qubits are capable of existing in multiple states simultaneously through quantum superposition, enabling them to store and process information far beyond the capabilities of classical bits.
This integrated chip not only generates quantum entanglement—where pairs of qubits share properties even when separated—but also performs encoding and transmission within a compact, scalable platform. Such integration is crucial for the future of quantum networking, which aims to interconnect quantum systems across long distances and ultimately form a secure, high-speed quantum internet.
According to lead author Joe Lukens, a senior researcher at ORNL and associate professor at Purdue University, “We’re not the first to put any one of these elements on a chip, but we’re the first to combine these specific quantum capabilities in one device. What’s exciting is that these chips can be manufactured using standardized processes, making mass production and real-world deployment much more feasible.” Lukens emphasized the shift from lab-scale demonstrations to scalable systems that could be used across industries.
The team’s chip enables broadband polarization entanglement—a technique that uses the directional vibration of light waves to encode information across a wide range of wavelengths. This kind of entanglement allows photonic qubits to travel through conventional fiber-optic networks, bypassing the need for specialized quantum infrastructure and lowering deployment costs. The photonic platform’s compatibility with telecom equipment could make the rollout of a quantum internet faster, cheaper, and more stable.
While creating and encoding photonic qubits is currently expensive and complex, ORNL researchers believe that integrated photonics like the chip they’ve developed will help simplify and scale the process. “Mass production means no more aligning sensitive optical components on a lab bench,” said Alexander Miloshevsky, an ORNL postdoctoral researcher and co-author. “Instead, it becomes a matter of plugging in a chip that already contains everything we need.”
At the core of the chip are critical components such as microring resonators, which generate entangled photon pairs, and polarization splitter-rotators that route light based on its polarization. These components work together to produce and manage entangled photons directly on the chip, streamlining the generation of broadband polarization entanglement.
“These photons are ready to go—they’re compatible with the fiber-optic cables already installed around the world,” said Hsuan-Hao Lu, an ORNL quantum research scientist. “Once we can generate and manipulate them effectively, much of the remaining infrastructure can rely on standard telecom gear.”
The chip also demonstrated record-breaking channel performance, with over 116 distinct channel pairs—essentially colors of light—available for transmitting entangled qubits. More than 100 of these channels maintained high fidelity, marking what the team described as a new benchmark in channel capacity. Thanks to the microring resonator design, the chip could potentially produce hyperentangled qubits—entangled not just by polarization but by multiple properties like wavelength, significantly expanding the data-carrying capacity of each qubit.
Joe Lukens explained, “Think of it like using pairs of quantum dice that always match results no matter how many times you roll them. Now imagine each die has more than one face for different properties—color, polarization, etc. That’s what hyperentanglement gives us: more ways to encode and communicate information simultaneously.”
This achievement represents a critical piece of the broader effort to realize a functional quantum internet. While the final architecture of such a network is still unknown, the development of chips like this one moves researchers closer to building reliable, scalable, and secure quantum systems that can eventually interconnect across the globe.
By Impact Lab
