ExpandQISE: Track 1: Spectrally-multiplexed Photon-pair Sources for Quantum Sensing and Networking

Quantum Information Science and Engineering (QISE) is on the verge of transforming many technologies including computing, sensing and communications. Individual 'particles' of light, photons, are ideal carriers of quantum information over large distances. This project is focused on the development of quantum light sources that produce pairs of photons, which provide an essential resource for QISE, that is also compatible with existing telecommunication infrastructure. The project, led by the University of North Dakota (UND), leverages UND's new cleanroom facilities to establish expertise in optical thin films and device fabrication, while partnering with the University of Oregon (UO) to benefit from its expertise in characterizing quantum light sources and its strong track record in QISE education. This partnership strengthens existing efforts to recruit, retain, and graduate undergraduate and graduate participants from underrepresented groups in STEM while establishing a framework to train the next generation of quantum scientists and engineers.

Sources of entangled photon pairs and single photons are critical elements of QISE. To advance the state of the art in sources of entangled photon pairs and heralded single photons based on spontaneous parametric down conversion (SPDC), the project focuses on a narrowband, frequency-multiplexed source of photon pairs based on cavity-enhanced SPDC. The semi-integrated design, where nonlinear bulk crystals are combined with dielectric thin film coatings fabricated in-house at UND, can be deployed in relevant environments for telecommunication and sensing. Multiplexing the source across multiple spectral bins addresses the fundamental limits to single pair emission rates. The design integrates with commercial and already deployed frequency multiplexed hardware. Narrowband photons can also be used in ways that differ from those photons generated with the established broadband sources. The pulse shape created by the cavity ringdown is more compatible with several platforms of quantum memories, which mostly require narrowband photons with a Lorentzian spectrum. The experimental milestones of this project include developing narrow-band, frequency-multiplexed photon pair sources and methods for characterizing these states, leveraging the unique capabilities of the project partners. The educational and outreach activities focus on providing access to QISE in rural areas.