  Optically-addressable solid-state spin defects are promising candidates for
storing and manipulating quantum information using their long coherence ground
state manifold; individual defects can be entangled using photon-photon
interactions, offering a path toward large scale quantum photonic networks.
Quantum computing protocols place strict limits on the acceptable photon losses
in the system. These low-loss requirements cannot be achieved without photonic
engineering, but are attainable if combined with state-of-the-art nanophotonic
technologies. However, most materials that host spin defects are challenging to
process: as a result, the performance of quantum photonic devices is orders of
magnitude behind that of their classical counterparts. Silicon carbide (SiC) is
well-suited to bridge the classical-quantum photonics gap, since it hosts
promising optically-addressable spin defects and can be processed into
SiC-on-insulator for scalable, integrated photonics. In this Perspective, we
discuss recent progress toward the development of scalable quantum photonic
technologies based on solid state spins in silicon carbide, and discuss current
challenges and future directions.
