quantum electro-optic amplifiers for the next generation quantum and supercomputers

ongoing

Quantum computers face many bottlenecks towards upscaling the number of qubits and increasing their computational power. One of them is the radio frequency (RF) -bottleneck between the qubit processor inside the cryostat and the room temperature control and readout electronics. And like for their classical counterparts, hope lies in replacing the RF-links by optical fibers, resulting in a hybrid situation where RF-qubits will be used for computation and optical qubits will serve for remote communication. However, electro-optical (EO) devices that parametrically amplify RF-qubits directly to optical qubits and vice versa have thus far remained elusive. Q-Amp will demonstrate a new class of EO-amplifiers that realize the required unity efficiency to achieve this goal. This is impossible with current EO-architectures which suffer from a deleterious trade-off between EO interaction strength (g) and EO losses (Q-factors). This originates from their device design and enhancing g requires bringing the RF-superconducting circuit in close vicinity of the optical waveguide, which comes at the expanse of excess EO losses. To cope with this, we will pioneer a transparent EO device technology that enhances g without the need of bringing superconductors and optical waveguides in close vicinity of each other. We will do so by concentrating the RF- and the optical field in the same nanoscale interaction volume via dipolar screening in ferroelectrics and/or ballistic transport in graphene. Confining both fields within next generation EO-materials will enable an increase of g from 100s of Hz (prior art) to Megahertz-levels. Simultaneously, light is kept away from the lossy superconducting electrodes enabling moderate Q-values of 1E5..1E6. Q-amp’s EO-amplifiers will finally overcome the scaling limitations of current superconducting quantum computers and will provide classical superconducting supercomputers with high-speed EO gateways they desperately need.