New faculty Dragic explores next-generation optical fibers

Reliable and ubiquitous, optical fibers carry long-distance phone calls and Internet data around the world, guide military weapon systems, underpin smart highways, and monitor deep-sea oil wells, to name just a few applications. However silica fibers are reaching their information-carrying capacity limits because of phenomena known as nonlinear optical effects, of which there are several variants.

MNTL faculty affiliate Peter Dragic is conducting research to overcome these non-linear effects, which are interactions between light and matter that limit the power output of optical fibers. One such phenomenon, Stimulated Brillouin scattering, is a deleterious coupling between optical and acoustic waves.  In 2013, Dragic and a colleague at Clemson University demonstrated a fiber that had the lowest recorded strength of this nonlinear process and predicted that it could be completely removed.

They achieved this milestone by expanding the materials pallet from which fibers are made, exploring materials like sapphire, yttrium-aluminum-garnet, spinel, and barium oxide instead of relying solely on silica and common dopants such as GeO₂ or P₂O₅.

  “Everyone uses mainly silica in fibers because it is cheap and abundant,” said Dragic, a former lecturer in the Electrical & Computer Engineering Department who recently became a tenure track faculty member. “What I’ve done is to try a materials science approach to overcoming the nonlinear phenomena, and it turns out if you monkey with the materials you can come up with a composition whereby the Brillouin scattering process is removed.  This methodology can be applied to other nonlinear processes as well.”

Dragic and his Clemson colleague have also made fibers from silica and lithia, a promising combination that he plans to develop into sensors that could be used to monitor the structural health of bridges and buildings. The silica-lithia fibers are less susceptible to temperature swings than silica-alone fibers.

Now that he has some proof-of-concept fibers, Dragic will focus his MNTL research on developing them into fiber-optic systems and lasers, which other research groups can use to conduct atmospheric studies or other projects. “MNTL is like a vertically integrated system where you have the potential to make everything,” he said. “MNTL has the facilities to make the wafers, grow the semiconductor laser sources, and integrate optical fibers."

As a former lecturer, Dragic has taught many ECE courses, including Fields and Waves I-II (ECE 329 & 350), Optical Communication Systems & Lab (ECE 465-466), Photonic Device Lab (ECE 495), and Optical Imaging (ECE 460). He looks forward to teaching the ECE 329 course in the fall 2016 semester. Previously, he created a project-based course and lab for the Illinois Foundry for Innovation in Engineering Education (iFoundry), which has enhanced the undergraduate learning experience in entrepreneurial ways.

An Illinois alumnus, Dragic (BSEE 1995, PhD 1999) worked for a telecom startup for three years before returning to his alma mater.