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We have developed a coaxial-type holographic disk system with a small drive. We achieved stable operation without use of a vibration-isolating table, with a 91-Mbps data-transfer rate for recording and retrieving using LDPC code.

We have shown that the signal loss induced by the media temperature change in the coaxial holographic recording can be compensated by tuning the magnification and the wavelength of the reading reference beam appropriately. This technique offers a significant improvement in the temperature tolerance of the coaxial holographic data storage.

We have experimentally evaluated the coherent addition technique, and revealed that the coherent addition can enhance detected data intensity and realize clear three-level data retrieving. Moreover, we have achieved great improvements in the multiplexed performance, which are the SNR gain of +3.5 dB and the data density increase with the factor of 2. We consider that this technique will strongly contribute to future holographic technologies.

We have applied LDPC codes into our coaxial recording system, and revealed its fundamental characteristics. In addition, by applying the E(16, 3, 8) code and optimizing optical conditions, we have successfully improved the recording density, achieving the raw data density of 415 Gbit/in.2.