Federal agency name: defense advanced research projects agency (DARPA), defense sciences office (DSO) funding opportunity title: young faculty award (YFA) funding opportunity number:…

The Department of the Interior Departmental Offices Interior Business Center awarded the University of Illinois a $500,000 cooperative agreement on September 30, 2025, under DARPA's Young Faculty Award program (CFDA 12.910, Research and Technology Development). The award funds research on microwave-to-optical interconnects for superconducting quantum computing circuits, leveraging a novel nonlinear photonic material with record cryogenic performance to reduce thermal loads and enable modular quantum computing over optical fiber. The research investigates scaled optical ingress and egress capabilities for delivering millions of control signals to millikelvin environments without introducing significant heating. Performance occurs in Illinois through September 29, 2027. The Young Faculty Award solicits innovative research proposals across DARPA's Defense Sciences Office, Information Innovation Office, Microsystems Technology Office, and Tactical Technology Office, emphasizing revolutionary advances in science, devices, or systems rather than evolutionary improvements to existing practice.

Federal agency name: defense advanced research projects agency (DARPA), defense sciences office (DSO) funding opportunity title: young faculty award (YFA) funding opportunity number: DARPARA2501CATALOG of federal domestic assistance (cfda) number(s): 12.910 research and technology developmentprogram description: DARPA is soliciting innovative research proposals in the areas of interest to the following DARPA technical offices: defense sciences office (DSO), information innovation office (I2O), microsystems technology office (MTO), and the tactical technology office (TTO). Further detail regarding the specific technical areas of interest can be found below under open office topics. Proposed research should investigate innovative approaches that enable revolutionary advances in science, devices, or systems. Specifically excluded is research that primarily results in evolutionary improvements to the existing state of practice. Scaling superconducting circuits desires microwave-to-optical interconnects that reduce wiring heat loads and enable modular quantum computing over optical fiber, which has intrinsically strong thermal insulation. We propose to use a totally new nonlinear photonic material which displays record cryogenic performance, developed by PI ANDERSON1,2, to make these interconnects orders of magnitude more efficient than before, reducing thermal load. The extremely low thermal conductivity of optical fibers combined with their high intrinsic bandwidth allows for the direct delivery of millions of control signals to the millikelvin environments where superconducting circuits operate without introducing significant heating. Previous work exploring this opportunity has focused on optical ingress into cryogenic environments with fast photodetection but lacked an egress CAPABILITY3. Other work used theelectro-optic nonlinearity of lithium niobate to read-out superconducting microwave circuits (egress), but desired materials with a higher pockels coefficient to reduce the added noise and outperform semiconductor microwave amplifiers, which are still the state-of-the-art (SOA)4. We propose to address this challenge by leveraging strontium titanate (STO) thin film optical modulators. Discovered by PI anderson, due to a unique low temperature quantum paraelectric phase, STO displays a cryogenic electro-optic pockels effect at least 20X stronger than SOA lithium niobate. This results in a potential 400X boost in interconnect performance for the same heat load, or a 400X reduction in active heating for each (QU)bit communicated from room temperature to cryogenic environments. Using STO, which specifically has optimal performance at cryogenic temperatures, thermally insulating optical interconnects can be enabled that outperform high-electron mobility transistor (hemt) amplifiers. This would unlock the scaling of superconducting quantum and rapid single flux quantum (rsfq) cryogenic classical COMPUTERS5. To achieve this impact, developing STO thin film photonic devices thatoperate cryogenically are needed. Our reports of the pockels effect in STO have only been for bulk crystals. However, we have already created our own high quality STO-on-insulator films, but their use for cryogenic interconnects remains unexplored- the key technical challenge addressed here. This presents an exciting new opportunity for realizing the increased performance of these photonic modulators with superconducting devices for the first time. We will fabricate wide bandwidth microwave waveguides CO-integrated with STO rib opticalwaveguides and experimentally characterize their performance as an interconnect. Heat load, gain, efficiency, and added noise will be benchmarked against existing technologies, aiming for a 20 DB improvement over the SOA- rivalling traditional hemts.