title: Precise tailoring of acoustic velocity in optical fibers by hydrogenation and UV exposure.
abstract: Tailoring of acoustic properties in solids has many potential applications in both acoustics, i.e. acoustic gratings and waveguides, and photon-phonon interactions, i.e. stimulated Brillouin scattering (SBS). One immediate application is in the area of SBS suppression in optical fibers. We demonstrate, for the first time, a post-processing technique where hydrogen is diffused in to a fiber core and then locally and permanently bonded to core glass by a subsequent UV exposure. It is discovered that local acoustic velocity can be altered by as much as ~2% this way, with strong potential for much further improvements with an increased hydrogen pressure. It is also found that the large change in acoustic velocity is primarily due to a reduction in bulk modulus, possibly as a result of network bonds being broken up by the addition of OH bonds. It is possible to use this technique to precisely tailor acoustic velocity along a fiber for more optimized SBS suppression in a fiber amplifier. Change in Brillouin Stokes frequency of ~320MHz at 1.064μm was observed.
authors.affiliation: Center for Optical Materials Science and Technology/Department of Electric and Computer Engineering, Clemson University, Anderson, SC 29625, USA. fantink@clemson.edu
authors.forename: Fanting
authors.initials: F
authors.lastname: Kong
authors.forename: Liang
authors.initials: L
authors.lastname: Dong
mesh_terms: D000162:Acoustics; D000669:Amplifiers, Electronic; D004867:Equipment Design; D005336:Fiber Optic Technology / Q000295:instrumentation / Q000379:methods*; D006859:Hydrogen / Q000737:chemistry*; D007834:Lasers; D008962:Models, Theoretical; D055100:Optical Fibers; D017785:Photons; D012542:Scattering, Radiation; D014466:Ultraviolet Rays
chemical_list: D006859:Hydrogen