Optomechanical Microwave-to-Optical Photon Transducer Chips: Empowering the Quantum Internet Revolution

Abstract

The first quantum revolution has brought us the classical Internet and information technology. Today, as technology advances rapidly, the second quantum revolution quietly arrives, with a crucial moment for quantum technology to establish large-scale quantum networks. However, solid-state quantum bits (such as superconducting and semiconductor qubits) typically operate in the microwave frequency range, making it challenging to transmit signals over long distances. Therefore, there is an urgent need to develop quantum transducer chips capable of converting microwaves into optical photons in the communication band, since the thermal noise of optical photons at room temperature is negligible, rendering them an ideal information carrier for large-scale spatial communication. Such devices are important for connecting different physical platforms and efficiently transmitting quantum information. This paper focuses on the fast-developing field of optomechanical quantum transducers, which has flourished over the past decade, yielding numerous advanced achievements. We categorize transducers based on various mechanical resonators and discuss their principles of operation and their achievements. Based on existing research on optomechanical transducers, we compare the parameters of several mechanical resonators and analyze their advantages and limitations, as well as provide prospects for the future development of quantum transducers.

Keywords: optomechanics; quantum Internet; quantum chip; quantum transducer.

Figure 4

OMC cavity piezo-optomechanical (a,c–f) and electro-optomechanical (b,g,h) photon transducers. (a) Schematic diagram of phononic crystal simultaneously coupling with piezoelectric mechanical resonator and photonic crystal. (b) Schematic diagram of phononic crystal simultaneously coupling with electromechanical resonator and photonic crystal. (c) Room temperature OMC–Lamb wave IDTs transducer [69]. (d) OMC cavity piezo-optomechanical microwave-to-optical phonon transducer based on LN [66]. (e) Room temperature OMC cavity transducer based on LN [34]. (f) GaP microwave-to-optics transducer with low noise [67]. (g) Integrated OMC cavity electro-optomechanical photon transducer [61]. (h) Electro-optic transduction by OMC cavity transducer on SOI [31]. (c) is reprinted from Vainsencher et al., Appl. Phys. Lett. 109. 033107 (2016) [69] with the permission of AIP Publishing. (d,h) are reproduced from [31,66] under the terms of the Optica Open Access Publishing Agreement. (e–g) are reproduced from [34,61,67] under Creative Commons Attribution 4.0 International License.

Figure 1

Comparison of classical and quantum computer networks. The left illustrates the classical computer network where computers connect and communicate with each other via fiber-optic network interface. The right shows a quantum computer network, where transducers are used to convert quantum information for communication between the quantum server and other devices such as quantum computers, quantum sensors, and the quantum repeaters that can work as nodes in the network.

Figure 2

Schematic representation of the microwave-to-optical optomechanical transducer models. (a) Frequencies ${\omega }_i/2\pi$, bosonic operators ${\widehat{a}}_i$, and loss rates ${\kappa }_i$ of three coupled modes of the transducer: microwave (blue, $i=e$), optical (red, $i=o$), and mechanical (green, $i=m$). The microwave and optical photons couple to external channels with efficiency ${\eta }_e$ and ${\eta }_o$, and the mechanical mode with coupling rate $g_{em}$ and $g_{om}$, respectively. (b) Different models (platforms) during microwave-mechanical-optical conversion are covered in this review. In the middle are the mechanical resonators capable of simultaneously coupling with microwaves and optics. Specifically, SAW resonators, which can only achieve electromechanical coupling, are listed separately.

Figure 3

Membrane optomechanical systems: electromechanical resonator couples with FP optomechanical resonator using membrane as medium.

Figure 5

Microdisk cavity mediated optomechanical transducers. (a) Schematic diagram of microwave, acoustic, and optical modes of piezoelectric microdisk–WGM transducer. (b) AlN optomechanical microdisk cavity microwave–optical transducer. Reproduced from [37] under Creative Commons Attribution 4.0 International License.

Figure 6

BAW resonator mediated optomechanical transducers. (a) Simplified experimental schematic of the hybrid piezo-Brillouin optomechanical system. (b) Schematic diagram of microwave, acoustic, and optical modes of piezoelectric BAW-FP transducer. Reproduced from [39] under the terms of the Optica Open Access Publishing Agreement.