Fabrication of a hybrid-cladding tellurite glass fiber doped with Tm3+ and Ho3+

Abstract To improve the mechanical properties of tellurite glass fiber, a hybrid-cladding optical fiber with Tm3+/Ho3+ co-doped TeO2-WO3-La2O3 glass core, tellurite glass inner cladding and phosphate glass outer cladding was proposed and fabricated by rod in tube and twice drawing method in this work. The spectroscopic characteristics of the core glass were systematically investigated too, the results showed that the maximum emission cross section was about 7.91 × 10−21 cm2, the longest fluorescence lifetime at 2030 nm was 2.47 ms, the value of σem × τrad was 19.53 × 10−21 cm2ms, and the maximum gain coefficient was about 2.02 cm−1 when 1.2 mol% Tm3+ and 0.6 mol% Ho3+ were co-doped in tellurite glass. The hybrid-cladding tellurite glass fiber fabrication process was presented in detail. A single-mode glass fiber with hybrid-cladding was fabricated and NA1 of the core is 0.116, and NA2 of the inner cladding is 1.249 and is beneficial for pump light collection. The core diameter of which is 6.8 μm, and the fiber loss is 20.16 dB/m. The fabricated hybrid cladding glass fibers can be easily cut without obvious defect.