Continued progress in the development of optical fiber-based lasers has led to the present state where further improvements in performance are limited by intrinsic optical nonlinearities. In order to manage such limitations, laser designers have largely adopted the approach of microstructuring the fiber to shift nonlinear thresholds to high optical powers. The nonlinearities are accepted as fixed and performance is enhanced through fiber geometric complexity. This talk treats a different option, which is to mitigate optical nonlinearities at their fundamental origin: the materials with which the light interacts. This work provides a road-map for the development of simple core/clad optical fibers whose enhanced performance – in particular, marked reductions in optical nonlinearities – is achieved materially and not through the more conventional present routes of geometrically complex fiber design. More specifically, the material properties that give rise to Brillouin, Raman, and Rayleigh scattering, transverse mode instabilities (TMI), and n2-mediated nonlinear effects are compiled and results on a wide range of optical fibers are discussed with a focus on trends in performance with glass composition. Further, optical power scaling estimations as well as binary and ternary property diagrams associated with Rayleigh scattering, the Brillouin gain coefficient (BGC) and the thermo-optic coefficient (dn/dT) are developed and employed to graphically represent general trends with composition along with compositional targets for a single intrinsically low nonlinearity, silica-based optical fiber that can achieve the power-scaling goals of future high energy fiber laser applications.
John Ballato received the B.S. degree in ceramic science and engineering and the Ph.D. degree in ceramic and materials engineering, both from Rutgers, The State University of New Jersey, New Brunswick, NJ, USA, in 1993 and 1997, respectively. He is currently a Professor of materials science and engineering at Clemson University, Clemson, SC, USA, where he is the inaugural holder of the Sirrine Endowed Chair. He has published 400 technical papers and holds 34 U.S. and foreign patents. Among numerous other honors, his collaborative work on Anderson-localizing optical fiber was chosen as one of the Physics World’s Top Ten Breakthroughs for 2014. He is a Fellow of the Optical Society of America (OSA), the International Society of Optical Engineering (SPIE), the Institute of Electrical and Electronics Engineers (IEEE), and the American Ceramic Society (ACerS), as well as an elected member of the World Academy of Ceramics and the U.S. National Academy of Inventors.