Cryogenic Characterization off Electro-Optic Organics for Quantum Transduction

Cryogenic fiber-optic links offer a promising route to scale superconducting quantum processors by reducing the passive heat load of coaxial RF connections. A key integration strategy involves embedding electro-optical (EO) devices directly into superconducting qubit circuits. EO polymers are ideal candidates, with low dielectric constants and high Pockels coefficients, show excellent performance in classical modulators. Yet, cryogenic RF-loss characterization in the few-photon regime for EO polymers remain limited. Since EO polymers are amorphous, they are particularly susceptible to two-level system (TLS) losses [1]. Understanding their behavior in the few-photon regime is therefore an important aspect for future quantum device integration. We report a TLS loss tangent in the JRD1:PMMA EO polymer on the order of 7 × 10−4 , which is comparable to oxides. We present measurements on the optical propagation loss, Pockels coefficient, stability across multiple thermal cycles and radio-frequency losses of the JRD1:PMMA mixture before and after poling in order to assess the intrinsic limit imposed by the EO-polymer on quantum transduction.

[1] C. R. H. McRae, H. Wang, J. Gao, M. R. Vissers, T. Brecht, A. Dunsworth, D. P. Pappas, and J. Mutus. Materials loss measurements using superconducting microwave resonators. Review of Scientific Instruments, 91(9), September 2020.