Silicon T centre devices for quantum networks

The performance of modular, networked quantum technologies will be strongly dependent upon the quality of their light-matter interconnects. Solid-state colour centres, and in particular T centres in silicon, offer competitive technological and commercial advantages as the basis for quantum networking technologies and distributed quantum computing. These silicon defects offer direct telecommunications-band photonic emission, long-lived electron and nuclear spin qubits [1], and proven native integration into industry-standard, CMOS-compatible, silicon-on-insulator (SOI) photonic chips [2]. Here we present recent advances in integrated photonic T centre devices and determine previously unknown properties of the T centre to instruct their operation in both on-chip and distributed quantum networks. We demonstrate new levels of integration by characterizing T centres in single-mode waveguide devices in SOI including nanophotonic cavities. We find that the narrow homogeneous linewidth of these waveguide-integrated emitters is already sufficiently low to predict the future success of remote spin-entangling protocols with only modest cavity Purcell enhancements. Newly determined ground-state Hamiltonians illustrate how high-fidelity entanglement may be distributed over such a network, utilizing a local register of nuclear spin qubits at each T centre. These results cumulatively support the view that high-performance, large-scale distributed quantum technologies based upon T centres in silicon may be attainable in the near term [3].

[1] L. Bergeron, C. Chartrand, A.T.K. Kurkjian, et al. PRX Quantum 1 020301 (2020)

[2] D. B. Higginbottom, A. T. K. Kurkjian, C. Chartrand, et al. (2021). Optical observation of single spins in silicon. Nature  607, 266-270, (2022)

[3] X. Yan , S. Gitt,  B. Lin, et al. APL Photonics, 6 (7) (2021)