Hydrogen Prevents UV Damage in Optical Fiber

Hydrogen can fortify optical fibers, making them capable of sustained transmission of high-intensity UV light.

A team from the National Institute of Standards and Technology created the new fibers, which they said could help reduce errors in logic operations in quantum computing experiments.

Hydrogen has been shown to alter the performance of optical fibers, but the NIST researchers said they are the first to put this phenomenon to practical use, essentially healing damage caused by UV light as it occurs.

This micrograph shows an optical fiber that has been infused with hydrogen and cured with UV light. Courtesy of NIST.

A combination of hydrogen infusion and curing with ultraviolet light “appears to confer long-term resistance” to damage, the researchers said. The researchers said the fibers have low UV loss and also “clean up” misshapen light beams.

The researchers tested fibers with solid cores made of fused silica surrounded by lattices of air holes; this formed a crystal structure that maintained the shape of transmitted laser beams.

The fibers were infused with hydrogen gas, at 100 times the standard atmospheric pressure, for four to six days. Once the hydrogen diffused into the fiber cores, those fibers were cured by exposure to ultraviolet laser light for several days.

The fibers did not display any solarization damage when transmitting 313-nm laser wavelengths, even at output powers as high as 125 mW, the researchers said. This is several times the beam intensity needed for quantum computing experiments, they said.

When used to trap ions, the fibers reduced stray light and fluctuations in laser beam pointing, and allowed UV transmission between separate optical tables, the researchers said.

The team also tested untreated fibers with 313-nm laser light at 100 mW power. Light transmission through the fibers dropped to zero within four hours, they said.

The research was published in Optics Express (doi: 10.1364/OE.22.019783).

For more information, visit www.nist.gov.