Scalable Sapphire Seen as Superior to Silica for Fiber Optics

Transforming scalable sapphire into a fiber that can withstand greater light intensity provides an easily accessible, low-cost solution for fiber optics using common materials.

Silica has been used as a fiber material for many years, but it cannot handle the increasing light intensity in fiber cables.

“We have used a highly purified version of beach sand (silica) for fiber for the last 40 years,” said John Ballato, director of the Center for Optical Materials Science and Engineering Technologies at Clemson University. “As a matter of fact, the 2009 Nobel Prize in physics was awarded for the development of silica optical fibers. However, while silica has done remarkably well over time, it is now being pushed to its limits for faster and cheaper data, and new functionality.”

Silica now actually interacts and rebels against the light packed in fiber cables.

Sapphire has extraordinary properties and can withstand the intensity of light packed in fiber cables better than silica materials and is more useful for high-energy applications than typical commercial fibers, according to Clemson University researchers. (Image: John Ballato, Clemson University)

“At high power, the light causes the atoms of the material to vibrate more violently, and those vibrations convert some of the light energy into sound energy, which restricts the ability of the fiber to carry more power,” Ballato said. “This, in turn, lessens the amount of light that can travel through the fiber, which limits the amount of information that can be sent for telecommunications uses and power for high-energy laser applications.”

Ballato and colleagues discovered that sapphire has extraordinary properties that make it suitable for high-power lasers in which light intensity interplays with sound waves in the glass, resulting in reduced power-handling capabilities.

“Sapphire is new and different in this sense because we’re able to use a low-cost and widely used commodity as a fiber,” he said. “Sapphire is scalable, acceptable, and is a material that people don’t think about when it comes to fiber optics. The problem is that sapphire’s crystalline structure is not amenable to making into optical fiber using commercially accepted methods.”

Ballato created the sapphire fiber to withstand the brunt of higher intensity and to be more useful for high-energy applications than conventional commercial fibers.

“Ballato’s recent results with sapphire fibers represent a paradigm-shifting development in the field of fiber optics,” said Siddarth Ramachandran, associate professor in the electrical and computer engineering department at Boston University and an expert in the field. “Materials long considered to be used only in the realm of free-space optics can now be exploited in fiber geometries, which enable long interaction lengths and novel nonlinear optical effects.”

Ballato’s team is conducting further analyses with sapphire and other materials that demonstrate similar effects for fiber.

The findings were reported in Nature Photonics.

For more information, visit: www.clemson.edu