Using computer simulations, researchers at Hokkaido University, ThePennsylvania State University and their industry collaborators havetheoretically shown that signal loss from silica glass fibres can be reduced bymore than 50%, which could dramatically extend the distance data can betransmitted without the need for amplification.
“Improvements in silica glass, the most important material for opticalcommunication, have stalled in recent years due to lack of understanding of thematerial on the atomic level,” says Associate Professor Madoka Ono of HokkaidoUniversity’s Research Institute of Electronic Science (RIES). “Our findings cannow help guide future physical experiments and production processes, though itwill be technically challenging.”
Ono and her collaborators used multiple computational methods to predictwhat happens to the atomic structure of silica glass under high temperature andhigh pressure. They found large voids between silica atoms form when the glassis heated up and then cooled down, which is called quenching, under lowpressure. But when this process occurs under 4 gigapascals (GPa), most of thelarge voids disappear and the glass takes on a much more uniform latticestructure.
Specifically, the models show that the glass goes under a physicaltransformation, and smaller rings of atoms are eliminated or “pruned” allowinglarger rings to join more closely together. This helps to reduce the number oflarge voids and the average size of voids, which cause light scattering, anddecrease signal loss by more than 50 percent.
The researchers suspect even greater improvements can be achieved usinga slower cooling rate at higher pressure. The process could also be exploredfor other types of inorganic glass with similar structures. However, actuallymaking glass fibres under such high pressures at an industrial scale is verydifficult.
“Now that we know the ideal pressure, we hope this research will helpspur the development of high-pressure manufacturing devices that can producethis ultra-transparent silica glass,” Ono says.Madoka Ono is part of theLaboratory of Nanostructured Functional Materials, RIES at Hokkaido University.Her research focuses on the properties of non-organic and silica glass by bothlaboratory experiments and computational analyses.