Two-Way Photonic Interface for Linking the Sr+ Transition at 422 nm to the Telecommunication C Band
Thomas A. Wright, Robert J. A. Francis-Jones, Corin B. E. Gawith, Jonas N. Becker, Patrick M. Ledingham, Peter G. R. Smith, Joshua Nunn, Peter J. Mosley, Benjamin Brecht, Ian A. Walmsley · Physical Review Applied · 2018
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.