Electrical driving of X-band mechanical waves in a silicon photonic circuit

TL;DR

This paper demonstrates electrical driving and optical read-out of a high-frequency mechanical mode in a silicon photonic circuit, highlighting a new, efficient electro-mechanical modulation mechanism for integrated photonics.

Contribution

It introduces a capacitive electrical driving method for mechanical waves in silicon photonics, enabling scalable and efficient opto-electro-mechanical devices.

Findings

Mechanical mode at 7.2 GHz successfully driven electrically.

Optically read-out shows two orders of magnitude increased phase modulation efficiency.

Capacitive driving is adaptable to various material systems.

Abstract

Reducing energy dissipation is a central goal of classical and quantum technologies. Optics achieved great success in bringing down power consumption of long-distance communication links. With the rise of mobile, quantum and cloud technologies, it is essential to extend this success to shorter links. Electro-optic modulators are a crucial contributor of dissipation in such links. Numerous variations on important mechanisms such as free-carrier modulation and the Pockels effect are currently pursued, but there are few investigations of mechanical motion as an electro-optic mechanism in silicon. In this work, we demonstrate electrical driving and optical read-out of a 7.2 GHz mechanical mode of a silicon photonic waveguide. The electrical driving is capacitive and can be implemented in any material system. The measurements show that the mechanically-mediated optical phase modulation is two orders of magnitude more efficient than the background phase modulation in our system. Our demonstration is an important step towards efficient opto-electro-mechanical devices in a scalable photonic platform.