  Photonic integrated circuits (PICs) are expected to play a significant role
in the ongoing second quantum revolution, thanks to their stability and
scalability. Still, major upgrades are needed for available PIC platforms to
meet the demanding requirements of quantum devices. In this paper, we present a
review of our recent progress in upgrading an unconventional silicon photonics
platform towards such goal, including ultra-low propagation losses, low fibre
coupling losses, integration of superconducting elements, Faraday rotators,
fast and efficient detectors, as well as phase modulators with low loss and/or
low energy consumption. We show the relevance of our developments and of our
vision in two main applications: quantum key distribution - to achieve
significantly higher key rates and large-scale deployment - and cryogenic
quantum computers - to replace electrical connections to the cryostat with
optical fibres.
