Improvements in the capacity of computer-generated holographic storage using the Lee method with sparse multivalued reconstructions

The use of sparse multivalued data encodings for the purpose of increasing the capacity of parallel-access optical memories based on Fourier-transform computer-generated holography is discussed. Results based on the Lee method indicate that a sparse encoding of nonbinary data words can be used to increase the storage-area utilization efficiency from 35% to > 70%. It is also found that for signal-to-noise ratios greater than 200, five-level data encoding can be used to achieve bit error rates less than 10−12 reliably with 60% area efficiency.