Cavity-Integrated Electro-Optics (CIELO)

Modern technology relies on two distinct “languages” to process and move information. Superconducting quantum computers, which operate at temperatures near absolute zero, communicate using “microwaves.” In contrast, the high-speed fiber-optic cables of our global internet use “light.” The challenge is that these two signals do not naturally interact: microwaves are fragile and easily overwhelmed by heat, while light carries enough energy to disrupt the delicate quantum states of a superconducting processor. Pillar 4 serves as the “translator” for these two worlds. Rather than forcing a direct, perfect conversion between them—which is technically daunting—the CIELO team uses a “shortcut” called quantum teleportation. This method creates a shared connection, or entanglement, between light and microwaves to move information safely from a chip to a network.

The core mission of pillar 4 is to realize electro-optic interfaces that can operate in this sensitive single-photon-level regime to entangle or control quantum circuits. To achieve this, the project has set four specific goals: measuring the unique “quantum” signatures between microwave and optical photons, demonstrating a “remote” quantum connection at room temperature, performing an optical readout and control of a superconducting qubit, and developing low-noise optical readout for large arrays of cryogenic detectors. By replacing bulky coaxial cables with optical fiber, we show a new way to scale up quantum computers and connect them over long distances.

• Strategic Shift: We have moved toward a “teleportation” model, which is more robust against signal loss than direct conversion. (ISTA, EPFL)
• High-Speed Integration: We demonstrated high-speed modulators integrated directly with superconducting circuits. (EPFL)
• Heat Management: integrating advanced materials like organic polymers and specialized crystals directly with quantum circuits to minimize the thermal loads that typically plague these systems. (ISTA)