Two-Way Photonic Interface for Linking the Sr+ Transition at 422 nm to the Telecommunication C Band

Trapped ions have achieved the highest fidelity in local processing of quantum information, but their short emission wavelengths are incompatible with long-distance distribution of information at telecom wavelengths, which prevents their use in a large-scale quantum network. We present an interface capable of two-way frequency conversion of single photons between a Sr⁺ node-compatible wavelength and the telecom C band, forming part of a critical pathway for future hybrid light-matter quantum networks. This scheme offers bidirectional translation of widely separated frequencies in a single stage, with noise levels low enough for high-fidelity interconnects.