Towards the development of a microwave to millimeter-wave quantum frequency converter

Quantum networks of microwave superconducting qubits may require the conversion of photons from microwave frequency to those of higher energy for transmission over thermal channels. An approach pursued across the field is to use a three-wave mixing nonlinearity to convert microwave photons to optical photons, so that optical fibers can be used as links for long-range connections. However, these systems’ conversion rate is inherently limited by optical-loss-induced heating. We pursue conversion between microwave (1-10 GHz) signals to millimeter-wave (mmWave, 50-300 GHz) signals, which has the potential to increase the conversion rate by nearly nine orders of magnitude and allow transmission with low decoherence over tens of meters. This talk will outline our experimental approach to a microwave-mmWave conversion scheme, where high bandwidth and high rate interconnects can be created at the laboratory scale. We design and implement multi-frequency antennae, with two modes in the mmWave frequency band, and one mode in the microwave frequency band. We will present recent experimental results as well as outlining possible applications in quantum sensing.