Ince-gauss based multiple intermodal phase-matched third-harmonic generations in a step-index silica optical fiber

摘要

Several third harmonic generation processes were performed in a single step index germanium doped silica optical fiber under intermodal phase matching conditions. The nanosecond fundamental beam range between 1400 and 1600 nm. The transverse distributions of the energy were successfully modeled in the form of Ince-Gauss modes, pointing out some ellipticity of fiber core. From these experiments and theoretical calculations, we discuss the implementation of frequency degenerated triple photon generation that shares the same phase matching condition as third harmonic generation, which is its reverse process. (C) 2015 Elsevier B.V. All rights reserved.