We experimentally demonstrated the plification of optical disc readout signals by homodyne detection . This technique uses optical interference to amplify the signals . We fUrther apPlied p hase − diversity detection to reliabiy obtain the amplified reado ut sign aL The optical system was carefU lly designed so that suffieient stability is assu red and a su 盤 ciently amplified readout signal can be obtained . We experimentally demonstrated a 3. 6 times amplifcation ofa B lu − ray Disc readout

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... gnaL The present technique will be essentia1 for the real commercialization ofnext − generation multilayer optical disc because ofits outstanding ability ofsignal − to − noise ratio improvement.