Although fiber optic cables have made communication and data transfer even faster than previously possible, they are still subject to physical limitations and data loss. A new study has found a way to reduce signal losses from glass-based optical cables.
Researchers from the US state of Penn State and AGC Inc. in Japan they suggest that the silicon dioxide used in the manufacture of these cables be produced under high pressure conditions.
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PHILADELPHIA – SEPTEMBER 12: An optical cable was seen in a “multisensory room” at Elwyn Baring Street Center on September 12, 2002, in Philadelphia, Pennsylvania.
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Signal loss in optical cables
“Signal loss means we have to use amplifiers every 80 to 100 miles (50 to 62 miles),” John C. Mauro, a professor of materials science and engineering in Penn State, said in a press release. He adds that after that distance, the signals are no longer “detected correctly”, which becomes a significant problem on the continents and oceans.
Inevitable signal losses in glass fibers occur due to Rayleigh scattering – light scattering and other forms of electromagnetic radiation, due to imperfections in the atomic structure of the medium. Mauro notices the accidental presence of open porosity or voids in the atomic scale. The wires used in the construction of optical cables are made of ultra high purity silicon glass.
“Historically, the biggest breakthrough was the discovery that led to the original optical fiber – how to get rid of water in a glass,” Mauro added, noting the presence of water. It absorbs the signal, especially the one below the frequencies commonly used for telecommunications. But with a specialized technique based on the deposition of chemical vapors, water can be removed from silicon fibers.
Existing techniques for the production of optical cables are done close to the conditions of ambient pressure.
Researching the impact of pressures on the production process
The researchers conducted molecular simulations to investigate the effects of pressure in the fabrication process, and the results of their study were published in the journal NPJ Computational Materials. According to the simulation, more than half of Rayleigh’s scattering losses could be reduced by pressure by tempering the glass.
The report explains that by applying additional pressure to the material it becomes less heterogeneous. It also reduces gaps in the atomic scale – making the material more homogeneous and less porous.
While the Penn State team worked on a simulation of increased pressure on the glass, Madoka Ono conducted actual tests on silicate glass batches and found that the results confirmed the simulation. It is affiliated with Materials Integration Laboratories AGC Inc. and is an associate professor at the Institute of Electronic Sciences, University of Hokkaido.
Mauro said in a statement from the state of Penn State that the optimal pressure is around four gigapascals (GPa). However, this is not a direct improvement in the optical fiber production process. To be produced under these extreme pressures, it would have to form and cool under pressure during the glass transition phase – when the glass is between its solid and liquid phases and looks like a viscous material. A specialized chamber that can hold 40,000 atmospheres of pressure would be needed.
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See more news and information about fiber optics in the Science Times.