High Density Fiber Optic Packaging for Cryogenic Applications

A quantum network may use long-lived quantum memories with optical interfaces incorporated into a scalable architecture. Color-center quantum emitters in diamond have emerged as a promising quantum-memory modality due to their optical properties and compatibility with scalable integration. Here, we disclose a cryogenically stable and network-compatible quantum-emitter module for use as a quantum memory. This quantum-emitter module includes a diamond microchiplet with quantum emitters in the form of silicon vacancies or other color centers. The diamond microchiplet is integrated with a silicon photonic integrated circuit (PIC), which is secured to a silicon bench with cryo-compatible epoxy. Waveguides in the PIC are butt-coupled to optical fibers in a silicon V-groove array, which is secured to the same silicon bench with more cryo-compatible epoxy. A fast-curing epoxy holds the V-groove array to the PIC while the cryo-compatible epoxy cures for mechanical stability from room temperature to cryogenic temperatures.