  We report experimental storage and retrieval of weak coherent states of light
at telecommunication wavelengths using erbium ions doped into a solid. We use
two photon echo based quantum storage protocols. The first one is based on
controlled reversible inhomogeneous broadening (CRIB). It allows the retrieval
of the light on demand by controlling the collective atomic coherence with an
external electric field, via the linear Stark effect. We study how atoms in the
excited state affect the signal to noise ratio of the CRIB memory. Additionally
we show how CRIB can be used to modify the temporal width of the retrieved
light pulse. The second protocol is based on atomic frequency combs (AFC).
Using this protocol we also verify that the reversible mapping is phase
preserving by performing an interference experiment with a local oscillator.
These measurements are enabling steps towards solid state quantum memories at
telecommunication wavelengths. We also give an outlook on possible
improvements.
