Implementation of a quantum memory protocol based on the revival of silenced echo in orthogonal geometry at the telecommunication wavelength

An optical quantum memory protocol has been implemented on the basis of the revival of silenced echo at the telecommunication wavelength for signal light fields with a small number of photons. To this end, a long-lived ($>1$ s) absorption line has been initialized and the orthogonal geometry of the propagation of the signal and rephasing fields has been chosen. An efficiency of revival of $(17\pm177; 1)\%$ has been reached for the orthogonal polarization components of a signal pulse at a storage time of $60$ $\mu s$. The input pulse contains $\sim38$ photons on average, the revived echo signal includes $\sim6$ photons, and the signal-to-noise ratio is $1.3$.