An optical quantum memory protocol was implemented in the revival of silenced echo scheme in the 167Er3+:Y2SiO5 crystal at the telecommunication wavelength. The signal pulse recovery efficiency was 13% for a storage time of 60 μs for the optimal intensity of rephasing laser pulses. With a further increase in the laser pulse intensity, a superradiance pulse appears, causing a decrease in the signal pulse recovery efficiency. Methods for increasing the quantum memory efficiency by further increasing the pulse area of rephasing pulses are discussed.
Minnegaliev et al. (Wed,) studied this question.