Deuterium and particularly the hydroxyl ion with deuterium in it replaces the regular hydroxyl ion in the production of fibre optic cables or fibre optic lines. That allows much more light to pass through. The conventional way of doing it blocks about 30% of the light. If instead you use a deuterium technology, then you get much higher capacity in that fibre optic cable.
Again, this is developing customers in China, the United States, and Finland. They need a secure supply of deuterium oxide to expand and exploit that market, which slows down the pace of that innovation.