Recently, a research group at Tohoku University in Japan has developed crystallized fiberglass with a light transmittance of 90% or higher, which may be used in signal transmission and signal control like optical fibers. This will help achieve higher optical communication capacity.

Microscopic observation results of full-surface crystalline fiberglass: (a) Polarization microscope photo. As the crystallization heat treatment temperature decreases, the generation of vacancies is suppressed (left) and the crystal structure is homogenized (right). (b) Cross-sectional crystal orientation distribution by electron beam backscatter diffraction method. The c-axis of the Sr2TiSi2O8 crystal has a radially arranged directional structure, and a glass phase (black area) exists in the center part

        The research group developed a polycrystalline glass fiber with radially oriented crystallization in the radial direction, which is crystallized by adding excess titanium dioxide and silicon dioxide to strontium titanium silicon oxide. Excess components accumulate in the crystal gaps and fiber core to form a glassy phase.

        After the heat treatment temperature was lowered from 940°C to 800°C and extended from 1 hour to 36 hours, the vacancies were filled with glass and the light transmittance increased to more than 90% per centimeter, which is equivalent to optical single crystals.