CQIS: A Quantum Electro-Optic Converter
Quantum information science promises fundamentally new and vastly more powerful paradigms of computation, sensing, and communications. It also necessitates new classes of devices that are capable of processing quantum signals. One promising approach to engineered quantum systems uses low-temperature superconducting circuits to perform quantum information processing. These quantum machines are now being developed actively in academic, government, and industrial labs around the world. However, there is no way to connect these systems to one another across more than a few inches while preserving their important quantum properties. Creating links that traverse longer distances and leave the low temperature environments of the qubits demands converting the quantum information from a form suited for processing to another form suited for transmission, and vice versa. The objective of this research is to develop a device that can interconvert quantum information between optical and microwave frequencies. The quantum electro-optic converter being developed in this program promises to 1) connect these quantum machines to each other, 2) allow optical access to quantum nonlinearities at microwave frequencies, and 3) to simplify their scaling to larger numbers of superconducting qubits by allowing multiplexing of many microwave signals over an optical fiber. This will have a major impact on experimental quantum information science. Finally, the device will demonstrate for the first time quantum optical control of microwave circuits using laser light, which can enable new and unforeseen types of quantum sensing and communications capabilities at microwave frequencies.
Resonant acousto-optic devices in silicon for ultra-low power optical modulation and non-reciprocity
Currently, most high-speed optical switches and modulators, as well as all major industrial research efforts, are based on using electrons or electric fields to locally change the optical properties in material, leading to electrical control of optical fields. In contrast, this research program explores a novel approach using high frequency mechanical vibrations, or sound, in lieu of electrons to control the propagation of light. Remarkably, recent calculations and experimental results suggest the possibility of making optical high-speed modulators that operate nearly a thousand times more efficiently than state-of-the-art laboratory demonstrations, and more than one hundred thousand times more efficiently than commonly deployed technologies. This program will develop devices that experimentally demonstrate the potential of using sound to process light.
Our goal within this MURI is to make progress towards the quantum nonlinear regime of optomechanics - the last remaining and most challenging frontier of cavity-optomechanics requires strong coupling between single photons and single phonons in the resolved sideband limit. We will explore whether it is possible to engineer quantum nonlinearities between phonons, and if quantized motion can provide optical non-linearities at the single photon level. The most promising methods for producing non-classical states of mechanical oscillators will be investigated.
We thank the Stanford Graduate Fellowship and the National Science Foundation GRFP for their invaluable support.
Raphael van Laer is thankful for support from the FWO. Marek Pechal thanks the Swiss National Science Foundation.