Homodyne detection applied to bit-oriented holographic memories

A first experimental demonstration has been realized to inscribe and read by homodyne detection two wavelength multiplexed Bragg gratings in a BaTiO₃ photorefractive crystal. A red spectrally filtered superluminescent diode was used for both recording and readout. The 50% reflectivity mirror is mounted on a piezo stack. Oscillating this mirror at frequency with an amplitude of about 50 nm allows to detect the homodyne signal with a lock-in amplifier. Experimental data show good agreement with the modeling. In conclusion, homodyne detection seems particularly adapted to increase the data transfer rates of bit-oriented holographic memories.