Tunable third-harmonic generation in a chalcogenide-tellurite hybrid optical fiber with high refractive index difference

A chalcogenide-tellurite hybrid optical fiber with a step-index structure is fabricated by the rod-in-tube drawing technique. The core is made of 15Ge-3Ga-12Sb-70S (mol. %) glass, and the cladding is made of 78TeO2-5ZnO-12Li2O-5Bi2O3 (mol. %) glass. The refractive index difference Δn=0.24. Tunable third-harmonic generation from 568 to 869 nm is observed when the optical fiber is pumped by an optical parametric oscillator with the pump wavelength changing from 1700 to 2600 nm.