Experimental measurement of capacity vs. bit error rate for photorefractive holographic storage

Summary form only given. At the maximum capacity of a volume holographic storage, the next hologram would push the bit error rate (BER) over specification. The two effects that tend to increase BER as additional holograms are superimposed are interpage cross talk and the finite dynamic range (a decrease in diffraction efficiency per hologram in the presence of a constant noise floor). In the 90 geometry, the latter effect is dominant. There are other noise sources, however, that tend to be either independent of the number of holograms or dependent on the total optical exposure of the crystal. Examples of the former might be nonuniformities in the stored data page; of the latter, noise gratings and the photovoltaic noise buildup empirically observed in LiNbO/sub 3/:Fe.