Lighting the Way Forward

LIGHTING THE WAY FORWARD

By Michael Newman ’78
Photography by Craig Mahaffey ’98 and Ashley Jones

Today, data is moving at the speed of light. Clemson researchers are positioned in the center of an industry valued at nearly $8 trillion annually.

As he arrived for employee orientation in 1997, the newest member of Clemson’s ceramic engineering department could hardly know that a bigger milestone than the start of his academic career was about to take place — the birth of Clemson’s world-class fiber optics research and development program.

“I sat next to Dave Carroll, a new hire in the physics department, and over coffee later that day, we discovered that we had common interests in the optical properties of materials,” says John Ballato, professor of materials science and engineering and J.E. Sirrine Endowed Chair of Optical Fiber. “By the next day, we were in each other’s labs, sharing equipment and forging the collaboration that was the nucleus of an optical materials team at Clemson.”

Today, the flourishing fruit borne from that seed is the Center for Optical Materials Science and Engineering Technologies, or COMSET, a large-scale, interdisciplinary collaborative research center that Ballato, Carroll and three colleagues founded in 2000. In less than two decades, COMSET has positioned Clemson as an international leader in optical and optoelectronic materials, particularly fiber optics. Working closely with the private sector and the military, the group plays a key role in supporting and advancing the photonics industry that is valued globally at nearly $8 trillion annually.

COMSET’s list of credits and achievements is impressive. First and foremost, the center houses the only academic facility in the United States with industrial-scale capabilities for fabricating optical fiber. Served by 36 faculty from six departments, COMSET is home to two of Clemson’s four National Academy members, boasts three endowed chairs and six titled professors, has seeded more than 10 start-up companies, earned 10 researchers the National Science Foundation (NSF) prestigious CAREER Award, and over a five-year stretch has accounted for 6 percent of Clemson’s sponsored research from less than 2 percent of the University’s faculty.

The substance of that research is among the most diverse at Clemson, covering a broad spectrum of innovations, including advances, improvements and applications for high-power lasers; organic LEDs; light-emitting plastics, glasses and crystals; and even brain-stimulating optical nanoparticles.

As for why COMSET works so well, a recent external review conducted for the NSF of the center’s activities put it this way: “[COMSET] is a bit of a national treasure,” praised the reviewers, “… an extraordinary, coherent research program where all the pieces fit together perfectly.”

SEEING THE LIGHT

Some of the farthest-reaching advances from COMSET involve the design and creation of glass conduit that carries bits of data thousands of miles at the speed of light. These are called fiber optics, or optical fiber.

“Other than writing a letter or talking to someone in person, all other forms of data transmission and communication are conducted using light through an optical fiber,” Ballato says. “There would be no information technology as we know it today without fiber. No social media, no e-commerce, no movies-on-demand, no email, no internet … the list is endless.”

Optical fibers are long, thin strands of very pure glass about the diameter of a human hair. Their ability to carry light signals, most often infrared laser light, across long distances is maximized by arranging fibers into bundles known as cables. And yes, those are the cables that you hear about in ads when your telecommunications provider offers the latest package deal for phone, TV and internet service.
If you look closely at a single optical fiber, you will see that it has three distinct parts: the core, the thin-glass center through which the light travels; the cladding, a surrounding layer of glass that, like a continuous line of mirrors, reflects light back into the core along its entire length; and the buffer, a plastic sheath that protects the fiber from damage and environmental impacts.

The fiber works by keeping light moving forward through a process known as total internal reflection. As an illustration, imagine shining a flashlight down a hall. To get the light to travel around a corner into a second hallway, you would have to bounce the beam off a mirror. Multiple turns would necessitate that all the walls of all the hallways be lined with mirrors so that the original light could be transmitted along the entire path.
In the miniaturized version of the hallway example, light shone into a fiber optic cable travels through the fiber’s core by constantly bouncing off the cladding. Because the glasses comprising the fiber absorb a negligible amount of light, a single wave can be relayed forward for great distances.

Stephen Foulger is the director of COMSET and the Greg-Granitevillle Endowed Chair and Professor of Materials Science.

MAXIMIZING PERFORMANCE

While COMSET and Clemson’s fiber optics program have earned a top-tier level of respect and admiration, it wasn’t evident at the beginning that it would happen. Fortunately for both, a downturn in the economy was the timely spark toward success.

“When we were first setting up our fiber optics activities during the tail end of the dot-com boom in the late 1990s, most optical fiber research and development was focused on telecommunications,” Ballato says. “We knew that we couldn’t compete head-to-head with the established programs at that time, so we set our sights on an underserved community that needed specialty optical fibers: the U.S. military. We got in with the Defense Department, received funding, delivered top-quality fibers … and they kept coming back. So, when the telecommunications bubble burst in the early 2000s and fiber optics funding in that sector dried up, we were the ones still standing with world-class people, equipment, a dominant partner and best of all, a solid reputation.”

Ballato, who served as COMSET’s first director (2000–2014), says that reputation has continued to grow over the years, and along with it, the center’s clientele list. Among the more than 200 partners who have worked with COMSET during its 18-year existence are 3M, Baker Hughes, Lockheed Martin, Northrup Grumman, Raytheon, Sandia National Laboratories, and of course, the collaborator that made it all possible, the Department of Defense (DOD) through nine separate agencies and offices.

For Lawrence Grimes, director of DOD’s Joint Directed Energy Transition Office (recently changed from the High-Energy Laser Joint Technology Office) in Albuquerque, New Mexico, a nearly decade-and-a-half partnership with Clemson has proved invaluable.

“Since 2005, we’ve been working with Clemson’s fiber optics team to develop powerful lasers for use in directed energy weapons systems,” Grimes says. “One group, led by Dr. Ballato, has concentrated on creating novel glass materials that can operate at high intensity for long periods without losing strength. A second group, led by Dr. [Liang] Dong, has been identifying photonic crystal designs that permit us to upscale laser power as our needs become more and more demanding. Together, they have dramatically shortened the time from concept to battlefield for our technologies.”

The biggest challenge for fiber optics — and a major focus of Clemson’s research in the field, according to current COMSET director Stephen Foulger, has been finding ways to keep a fiber-transmitted light signal as strong at the end of its journey as at the beginning.

“Due to impurities in the glass of the fiber, some of the signal may be degraded or lost during transmission,” Foulger explains. “To minimize this problem and maximize the performance of optical fibers, you must improve the purity of the glass in the fibers — and that is primarily a materials problem because purity is dependent on the compounds used in the fabrication process and how they are incorporated into the process itself. Since COMSET started out as a materials program and has maintained that strength throughout its history, we are extremely well-suited to attack degradation issues.”

Ballato adds that COMSET has built upon its materials research foundation over time by selectively adding expertise and infrastructure in computer modeling, device fabrication and the science of critical components such as lasers. “Today, we can listen to the fiber optics needs of industry and government, design a fiber from scratch, model its performance before it is built, fabricate it to exacting specifications and test the resulting product to ensure it meets expected goals,” Ballato says. “No one else in the nation can provide that kind of ‘one-stop shop’ service at the academic level the way that we can.”

IN THE LAB

COMSET, which is headquartered at Clemson’s Advanced Materials Research Laboratory in Anderson, South Carolina, operates the Optical Fiber Laboratory, the nation’s only academic facility for fabricating industrial-grade optical fiber. The laboratory consists of two primary elements: a modified chemical vapor deposition (MCVD) lathe and an optical fiber draw tower.

The first step in making optical fibers is to create a glass cylinder, or preform blank, from which the hair-thin filaments will be drawn. That’s where the MCVD lathe goes to work. In this device, special solutions of silicon tetrachloride and germanium tetrachloride produce gas vapors, which in turn, are pumped through a pure glass tube attached to a rotating lathe. As the tube continuously turns, the gases react with oxygen at temperatures of nearly 4,000 degrees Fahrenheit, courtesy of a torch that moves up and down its length. The extreme heat forms ultrapure glass layers that are then consolidated into a solid rod. Once the rod cools, it is transferred to the draw tower for processing into the final optical fiber.

The draw tower gets its name from the fact that its components are vertically stacked one atop the other. A preform blank starts at the tower’s top, enters a graphite furnace (Clemson’s tower has three interchangeable heating units depending on the type of material being drawn) and is raised to temperatures as high as 4,000 degrees Fahrenheit, or hot enough to melt iron, until the tip becomes soft. Gravity pulls on the “gob” (often likened to a drop of water hanging from a leaky faucet) that forms, drawing it downward like an invisible spider spinning a glass filament. The strand is fed through a series of chambers and ultraviolet ovens that apply the fiber’s external plastic buffer coating and cure it, until it finally gets wound onto a tractor-driven spool. Laser micrometers along the path ensure that the desired fiber diameters are produced.

According to Foulger, the COMSET optical fiber fabrication labs can manufacture high-quality fibers with diameters ranging from about 100 microns (the size of a hair) to several millimeters. “The technology and tools that make all this possible are exorbitantly expensive to purchase and maintain, but the Clemson administration has always believed that COMSET should be a state-of-the-art, open-access facility that would facilitate innovation, encourage collaborations and partnerships, help win multimillion dollar research grants and grow the University’s research enterprise and reputation,” he says.

The modified chemical vapor deposition lathe
is used to create a glass cylinder.

AN INVALUABLE RESOURCE

Since its inception, COMSET has provided its faculty with the opportunity to be trailblazers, particularly in the fiber optics world given this unique infrastructure.

“We’ve invented and innovated a number of optical fiber technologies, including microstructured optical fiber lasers, semiconductor core optical fibers that marry microchip optoelectronics with the versatility of fibers and two kinds of optical fibers that exhibit fundamentally new ways to transmit laser light,” Ballato says proudly.

Both Ballato and his COMSET co-founder Foulger are contributing to the excitement with optics projects that are exploring some unchartered areas in the field. Ballato’s group is currently investigating how different glasses enable the properties of advanced, next-generation optical fibers while Foulger’s team — working under a $6 million grant from the National Science Foundation — is designing glass nanoparticles that one day may lodge near light-sensitive proteins in the brain, emit light and activate dormant or faulty brain functions.

Last year, Ballato and colleague Lin Zhu, associate professor of electrical and computer engineering, received $3.2 million from the Department of Defense to help design and build high-energy lasers with both potential industry and military applications. As with his previous DOD-funded projects, Ballato’s current research concentrates on improving the optical fiber used to transmit the laser beam. “The goal is for the laser light not to be affected at all by the material even when it’s brighter than the Sun,” he says. Zhu’s efforts focus on advancing the semiconductors and diodes used to convert electricity to laser light, making them more efficient so that the resulting beam is more precise.

The impact of this research and other projects like it at COMSET has brought the center a lot of customer loyalty.

“COMSET has proved an invaluable resource for us over the last decade, and that same dedication to excellence has propelled Clemson University into the top tier of fiber optics research institutes in the nation,” says longtime collaborator Bryce Samson, a senior executive with IPG Photonics in Oxford, Massachusetts. “There is no doubt that this success could not have been achieved in such a short period of time without the collective focus of the COMSET organization bringing together all the critical resources with a common goal.”

While its many technological achievements may be how most people measure COMSET’s success, Ballato and Foulger both believe that its greatest contributions are the many Clemson undergraduate and graduate students who have studied, trained and matured into expert scientists and engineers at this remarkable center.

“Because COMSET is unique among U.S. academic institutions, our students get more than just an education here; they become skilled, highly-sought professionals,” Ballato says. “There is nothing like working with students at COMSET, being with them when that light bulb goes on, and working with them on truly pioneering things that they couldn’t do in industry because of the more immediate need for product development.”

According to Foulger, that unique status and COMSET’s international recognition as an R&D leader could not have happened without the support and vision of Clemson’s administration.

“When our unconventional band of researchers formed COMSET back in 2000, the University leadership at that time clearly saw what was occurring and did everything they could to enable the effort,” he recalls. “They helped us organize into a center so that resources could be centralized and shared, they backed our building a world-class and distinctive infrastructure for researching optical fibers when only three other universities were even exploring the idea, and they stuck with our shared dream even during difficult financial times because they believed, based on our successes, that the investment would be returned.”

Michael Newman ’78 is a freelance medical, science and technology communicator who lives outside Washington, D.C.