We implement the ROSE protocol in an erbium doped solid, compatible with the telecom range. The ROSE scheme is an adaptation of the standard 2-pulse photon echo to make it suitable for a quantum memory. We observe an efficiency of 40% in a forward direction by using specific orientations of the light polarizations, magnetic field and crystal axes. The use of erbium doped materials has revolutionized fiber-optic communications. The erbium-doped fiber amplifier is a key enabling technology already emblematic of our century. Its transposition to the quantum communication world is an active subject of research showing interesting possibilities for long distance quantum cryptography [1,2].The direct use of erbium-doped fiber as an optical quantum memory is extremely appealing. Nevertheless the coherence time necessary to preserve the quantumness falls in the microsecond range even at subKelvin temperature [3]. Instead of amorphous materials [4], crystalline samples namely Er 3+ :Y 2 SiO 5 have shown remarkably long optical coherence time for solids [5]. These engaging properties are unfortunately counterbalanced by poor optical pumping dynamics. Spectral hole-burning (SHB) required by most of the quantum storage protocols is particularly challenging in erbium doped solids [6]. This intrinsic limitation is both due to the short lifetime of the population possibly shelved in the Zeeman sublevels (< 100 ms [6]) and to the long excited state population lifetime (∼ 10 ms). The ratio between the two timescales is not sufficient to obtain a good state preparation for optical thick samples. This simple experimental observation drastically bridles the implementation of quantum memories [7]. As an example, using the protocol named CRIB for controlled reversible inhomogeneous broadening derived from the photon- We recently proposed a protocol called Revival Of Si-

We study the bandwidth and multiplexing capacity of an erbium-doped optical memory for quantum storage purposes. We concentrate on the protocol revival of a silenced echo because it has the largest potential multiplexing capacity. Our analysis is applicable to other protocols that involve strong optical excitation. We show that the memory performance is limited by instantaneous spectral diffusion and we describe how this effect can be minimized to achieve optimal performance.