Volume holographic storage (VHS) is regarded as the best solution for cold (archival) storage. The advantages of VHS include high storage density, high security, low energy consumption, low cost, and long life. The essential advantages of NCU team is based on the world-leading design capability. Currently, the team has awarded 32 patents, and has built up a patent pool in securing the leadership in world-wide competition. The break-through technologies are as follows, migration compensation technology (patented, the only technology in the world); elimination of diffracted phase error (patented, and no comparable technology); largest temperature tolerance technology (patented) : the NCU＇s VHS disc can be increased to 10℃ rather than 2℃ in the other approaches; highest readout SNR record in the world (patented), the readout SNR of around 60, which is 10 times of 5 by SONY; VHS structured disc technology (patented) : 10 times storage capacity. (no comparable technology in the world)

All breakthrough technologies are patented. Migration compensation technology- this make the diffracted signal fixed while the VHS rotates during reading process. There is no comparable technology in the world. Elimination of diffracted phase error-this eliminates the induced phase error during readout process; the bit error rate can be dramatically reduced. High temperature tolerance technology-different from the others, it is free of adjusting laser wavelength. The temperature tolerance is the world record. Highest readout SNR record in the world-it utilizes a lens array to modulate the reference light and perform a theoretical highest readout SNR, which is 10 times of SONY. VHS structured disc technology-it creates a novel well-structure disc, and performs 10 times storage capacity.

Information explosion is a huge force to develop more powerful archival cold storage technology, which requires high density, low cost, high reliability, long life and high security. Nowadays, the major player is LTO, and blu-disc has become a potential competitor. But none of them could meet the demand in near future. The commercialized barrier of VHS has been conquered by NCU team through several creative inventions. Totally 32 patent-pool reduces the barrier of the new technology in commercialization, and is expected to replace LTO in the near future.