Fiber-coupled waveguide probe co-integrated with electrical control as a cryogenic photonic interface*

A key element for the characterization of nanophotonic spin qubit devices is the optical interface. Developing quantum photonic integrated circuits requires deterministic, reliable, and efficient coupling at cryogenic temperatures. Many current techniques to achieve high efficiency and reliable photon out-coupling require complicated cryogenic alignments specific to the device under test. Here we demonstrate a low-loss two-port optical interface for coupling to high quality factor silicon carbide resonators. This optical interface consists of a suspended fiber-coupled silicon carbide upon a silicon carrier chip that allows for stable and flexible probing of multiple photonic devices at cryogenic temperatures. We demonstrate mechanically controllable coupling, robustness to thermal cycling, and our work towards realizing simultaneous electrical and optical control of integrated photonic devices through the addition of electrical control lines within the carrier chip of the optical probe.