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Krister Shalm

Researchers at �鶹��Ѱ�����Boulder have advanced to the second phase of the Attosecond Synchronized Photonic Entanglement Network (ASPEN-Net), an effort to build a scalable quantum platform capable of distributing networks at high rates across large distances.

ASPEN-Net aims to develop the world’s most advanced quantum repeater network, operating thousands of times better than existing approaches. With these platforms, quantum can be leveraged across applications for computing and sensing technologies.

The National Science Foundation funded effort, led by the University of Oregon, is centered on the development of a large-scale quantum networking testbed that will be hosted by �鶹��Ѱ�����Boulder.

�鶹��Ѱ�����Boulder, along with the National Institute of Standards and Technology (NIST), is at the center of opening new capabilities in quantum networks, including the ability to connect quantum computers, deliver new forms of secure communications and connect remote sensors with extreme precision.

The endeavor is co-led by Professor Juliet Gopinath, professor of electrical engineering; Krister Shalm, a member of �鶹��Ѱ�����Boulder’s Quantum Engineering Initiative adjoint faculty member in the Department of Electrical, Computer and Energy Engineering and NIST quantum physicist; and Dileep Reddy, a senior research associate in the Physics Department, where they are combining their expertise in quantum engineering, photonics and physics.

“This next phase unlocks the ability for us to design a real, fieldable quantum system and perform proof-of-concept experiments,” said Gopinath. “We are excited to test new capabilities in quantum networking and carry out scientific experiments in an array of fields including metrology and astronomy.”

Juliet Gopinath

Precise timing tools not only enable new quantum repeater technology but also opens new clock synchronization capabilities essential for advanced positioning and navigation and applications.

Existing telecommunication technology, as Shalm notes, is fundamentally incompatible with the needs of a quantum network. Instead, one needs a device known as a quantum repeater to overcome the loss in communication networks.

“Right now, quantum repeaters are still in their infancy,” said Shalm. “Our aim is to build an advanced quantum repeater network through our testbed to enable new quantum applications and technologies.”

Leading universities collaborate quantum networking technologies��

A key goal of the �鶹��Ѱ�����Boulder-NIST testbed is the development of an attosecond-level timing layer.

An attosecond is a brief unit of time—a decimal point followed by 17 zeroes of a second. This allows researchers to monitor and compensate for fluctuations in the length of kilometers long deployed optical fibers that are the size of a single particle of smoke in a manner compatible with the highly sensitive single-photon-level quantum signals required for the network.

During the initial phase, researchers demonstrated attosecond-level stabilization of deployed optical fibers in a manner compatible with the highly sensitive single-photon-level quantum signals required for the network. This pushed the performance of entangled photon sources to meet the demands of a functional quantum network deployment.

Each testbed site contributes unique capabilities that complement the whole ASPEN-Net effort.

Dileep Reddy

�鶹��Ѱ�����Boulder will house ASPEN-Net’s main user facility, accessible both in-person to partners and remotely to the broader research community.��

Through the design phase, the �鶹��Ѱ�����Boulder team will perform initial demonstrations of the repeater technologies that will be eventually scaled up. The University of Oregon will focus on quantum sensing applications, including new quantum-enabled telescopes and the University of Illinois at Urbana-Champaign will explore connections to quantum computers.��

The ASPEN-Net team is supported by the Program Management Office (PMO) within the �鶹��Ѱ�����Boulder Research and Innovation Office. Kate Cochran and Julia Putt of the PMO serve as the project management team for the University of Oregon's prime award.

“By building interoperable quantum networks at each location, we will encourage a unified design that will lead to scaling quantum networks at a national scale,” Reddy said.

Doing so can help accelerate commercialization and move quantum networking technology out of the laboratory.

The design phase is expected to open significant new opportunities for �鶹��Ѱ�����Boulder undergraduate students, graduate students and postdoctoral researchers. ASPEN-Net is planning to actively expand its internship program and looking to engage early-career scientists in hands-on work designing a fieldable quantum network system.

Towards the end of the design phase, the consortium will have detailed plans for building out the three-site testbed proving a framework for future commercializing technologies.

“There are many unanswered questions about how to build quantum networks at scale that we aim to address," Shalm said. “Ultimately, this will allow us to build quantum repeaters for networks at a metropolitan-scale."

ASPEN-Net is a consortium of universities, national laboratories and industry partners. Original pilot sites include �鶹��Ѱ�����Boulder, University of Oregon, University of Illinois Urbana-Champaign, University of New Orleans and University of North Dakota. The Design Phase expands the consortium to include University of Massachusetts Amherst, Harvard University and additional partners from industry, academia and the public sector.��