Design and fabrication of large-scale diamond quantum memories in hybrid photonic circuits

A central goal in quantum information processing is the development of scalable quantum processors and quantum networks. Towards this end, solid-state “artificial atoms” such as color centers in diamond are especially promising because they combine efficient optical interfaces, minutes of spin coherence, and potentially very-large-scale fabrication. Here, we describe the design, fabrication, and integration of diamond quantum micro-chiplets containing single SiV and GeV centers with photonic integrated circuits (PICs). A near-deterministic photonic nanofabrication produces unity coupling of emitters to single-mode diamond waveguide arrays, which are subsequently assembled on an aluminum nitride PIC for on-chip routing and manipulation of photons. The combination of these advances allows the construction of a 72-channel quantum memory microphotonic chip. The ability to assemble large numbers of quantum memories with phase-stable PICs enables an architecture for high-efficiency, multiplexed quantum repeaters on a chip.