Telecom‐Integrated Photonic Memory Operating Near the Mechanical Ground State

ABSTRACT Scalable quantum networks require quantum memories that are chip‐integrated, telecom‐band compatible, and capable of flexible retrieval. Nanofabricated mechanical resonators meet these criteria. They offer independent tunability of optical and mechanical modes, long‐lived phonon states, and design flexibility beyond atomic systems, making them strong candidates for practical integrated quantum memory. Here, we demonstrate an on‐chip, absorptive optomechanical memory for telecom‐band photons, based on optomechanically induced transparency (OMIT) and operating near the mechanical ground state. The device stores telecom‐band photons, demonstrating compatibility with external photon sources at the few‐photon level, while enabling on‐demand retrieval. By placing the device in a dilution refrigerator at 20 mK and tailoring the control field to suppress optical heating, we achieve a remarkably low phonon occupancy of just 0.32 during the storage process. Our results lay the groundwork for scalable, phonon‐based quantum memory devices and open new avenues for integrating mechanical systems into practical quantum network architectures.