Third-harmonic generation in optical microfibers: From silica experiments to highly nonlinear glass prospects

Using optical microfibers, phase matching between different propagation modes allows for third-harmonic generation (THG). After detailing the relevant phase matching conditions and overlap integrals, we provide a comparison between THG effective efficiencies in silica and tellurite glasses. We also explain the relatively easy, wideband, conversion that we observe experimentally in silica glass microfibers, from 1.55 μm to the green, by the geometry of the tapering region.