# All optical operation of a superconducting photonic interface

## TL;DR

This paper demonstrates an all-optical interface for superconducting photonic circuits, enabling cryogenic operation without electrical interconnects, which could enhance quantum photonic processing and reduce noise.

## Contribution

It introduces a fully optical power delivery and signal extraction method for superconducting photonic devices, eliminating electrical interconnects at cryogenic temperatures.

## Key findings

- Successfully powered and read out SNSPD using optical interconnects
- Decouples cryogenic circuitry from external environment
- Potential for low-loss, high-bandwidth quantum photonic applications

## Abstract

Advanced electro-optic processing combines electrical control with optical modulation and detection. For quantum photonic applications these processes must be carried out at the single photon level with high efficiency and low noise. Integrated quantum photonics has made great strides achieving single photon manipulation by combining key components on integrated chips which are operated by external driving electronics. Nevertheless, electrical interconnects between driving electronics and the electro-optic components, some of which require cryogenic operating conditions, can introduce parasitic effects. Here we show an all-optical interface which simultaneously delivers the operation power to, and extracts the measurement signal from, an advanced photonic circuit, namely, bias and readout of a superconducting nanowire single photon detector (SNSPD) on a single stage in a 1K cryostat. To do so, we supply all power for the single photon detector, output signal conditioning, and electro-optic readout using optical interconnects alone, thereby fully decoupling the cryogenic circuitry from the external environment. This removes the need to heatsink electrical connections, and potentially offers low-loss, high-bandwidth signal processing. This method opens the possibility to operate other advanced electrically decoupled photonic circuits such as optical control and readout of superconducting circuits, and feedforward for photonic quantum computing.