  We investigated the optimal spectral design of periodic structure of narrow
lines (AFC-structure) within the inhomogeneously broadened atomic transition
which are created for the implementation of broadband AFC photon echo quantum
memory.The influence of the spectral design on the suppression of negative
dispersion effects in the AFC-echo retrieval was studied for different
spectroscopic parameters of atomic media. The maps of the assigned spectral
quantum efficiency have been constructed for the created AFC-structures
characterized by different spectral design, finesse and optical depth. Based on
the performed analysis, we discuss the possible ways for experimental
implementation of highly efficient broadband AFC-protocol.
