We demonstrate a photonic circuit with integrated long-lived quantum memories. Pre-selected quantum nodes - diamond micro-waveguides containing single, stable, and negatively charged nitrogen vacancy centers - are deterministically integrated into low-loss silicon nitride waveguides. Each quantum memory node efficiently couples into the single-mode waveguide (> 1 Mcps collected into the waveguide) and exhibits long spin coherence times of up to 120 {\mu}s. Our system facilitates the assembly of multiple quantum memories into a photonic integrated circuit with near unity yield, paving the way towards scalable quantum information processing.
@article{arxiv.1409.7965,
title = {Scalable integration of long-lived quantum memories into a photonic circuit},
author = {Sara L. Mouradian and Tim Schröder and Carl B. Poitras and Luozhou Li and Jordan Goldstein and Edward H. Chen and Jaime Cardenas and Matthew L. Markham and Daniel J. Twitchen and Michal Lipson and Dirk Englund},
journal= {arXiv preprint arXiv:1409.7965},
year = {2014}
}