The Evolution of Nanoparticles in Nanoparticle Doped Optical Fibers

Optical fiber and fiber laser technologies based on silica glass are critical to many technologies today. One method to improve the optical performance of laser fibers is engineer the local environment around the active elements in the glass. To that end, this Dissertation focused on the fabrication and characterization of fibers made with nanoparticles incorporated into the glass to control the local composition. First, the nanoparticle composition and structure was analyzed as it evolved from from the initially-synthesized form to incorporation into the dense aluminum-silicate glass. The aluminum oxide in the glass was found to be important not only to reduce phase separation but also to retain a higher concentration of the nanoparticle elements. Due to the small size and low concentrations of the modified regions in the glass, direct imaging of nanoparticle structures was unsuccessful, although several sample preparation techniques were explored. Nanoparticle-doped fibers were found to behave similarly to conventional silica glass optical fibers regarding refractive index and optical losses. Initial testing for potential applications showed that nanoparticle fibers have advantages for the design of fiber amplifiers and visible laser devices. While a definitive assessment of the benefits of nanoparticle optical fibers is beyond the scope of this research, several applications appear to benefit from the use of the fibers developed in this Dissertation.