Refractive index changes induced by ion beam implantation can be used to produce photonic
devices such as waveguides. Here, we relate the measured three-dimensional changes in refractive
index produced by ion beam implantation to modeling of the implantation process. We use a
quantitative phase microscopic method in conjunction with a tomographic reconstruction process to
determine the change in the refractive index distribution within a silica optical fiber that has been
selectively implanted with 2.4 MeV H+ ions. The index profile is compared with numerical
simulations of the ion vacancy and ionization using the stopping range of ions in matter program.