  Silicon is the ideal material for building electronic and photonic circuits
at scale. Spin qubits and integrated photonic quantum technologies in silicon
offer a promising path to scaling by leveraging advanced semiconductor
manufacturing and integration capabilities. However, the lack of deterministic
quantum light sources, two-photon gates, and spin-photon interfaces in silicon
poses a major challenge to scalability. In this work, we show a new type of
indistinguishable photon source in silicon photonics based on an artificial
atom. We show that a G center in a silicon waveguide can generate high-purity
telecom-band single photons. We perform high-resolution spectroscopy and
time-delayed two-photon interference to demonstrate the indistinguishability of
single photons emitted from a G center in a silicon waveguide. Our results show
that artificial atoms in silicon photonics can source highly coherent single
photons suitable for photonic quantum networks and processors.
