  Integrated quantum photonics offers a promising path to scale up quantum
optics experiments by miniaturizing and stabilizing complex laboratory setups.
Central elements of quantum integrated photonics are quantum emitters,
memories, detectors, and reconfigurable photonic circuits. In particular,
integrated detectors not only offer optical readout but, when interfaced with
reconfigurable circuits, allow feedback and adaptive control, crucial for
deterministic quantum teleportation, training of neural networks, and
stabilization of complex circuits. However, the heat generated by thermally
reconfigurable photonics is incompatible with heat-sensitive superconducting
single-photon detectors, and thus their on-chip co-integration remains elusive.
Here we show low-power microelectromechanical reconfiguration of integrated
photonic circuits interfaced with superconducting single-photon detectors on
the same chip. We demonstrate three key functionalities for photonic quantum
technologies: 28 dB high-extinction routing of classical and quantum light, 90
dB high-dynamic range single-photon detection, and stabilization of optical
excitation over 12 dB power variation. Our platform enables heat-load free
reconfigurable linear optics and adaptive control, critical for quantum state
preparation and quantum logic in large-scale quantum photonics applications.
