Preparation And Properties Of Er³⁺/Yb³⁺ Co-doped Double Cladding Bismuthate Glass Fiber

The laser near 1.5?m band located in the third communication window?1530-1565 nm?,which is safe for human eyes and has important application prospects in the fields of laser radar,biomedicine,energy exploration,and industrial manufacturing.At present,heavy metal oxide glass is a research hotspot of laser matrix glass materials in the1.5?m band.As a kind of heavy metal oxide glass,bismuthate glass has nice physicochemical properties,low phonon energy,high refractive index,and is considered to be an ideal matrix material for preparing infrared fiber devices.Therefore,this paper aims to explore a bismuthate glass system suitable for 1.5?m laser output.Based on this,the process of preparing Er³⁺/Yb³⁺ co-doped double cladding bismuthate glass fiber by rod-tube combination method and its 1.5?m band laser test were explored.The main research contents and conclusions of this paper are as follows:1.The effects of CeO₂ content on the thermal properties and spectral properties of Bi₂O₃-GeO₂-Ga₂O₃-Na₂O system glass were investigated.Studies have shown that as the CeO₂ content increases from 0 mol%to 0.4 mol%,the transmittance of the glass system increases significantly from 20%?n?CeO₂?=0 mol%? to 80%?n?CeO₂?=0.1-0.4 mol%?,and the?T value increases from 118? to a maximum of 126?.As the CeO₂ content increases to 0.8 mol%,the?T value decreases to 70?,and when the CeO₂ content increases to 1.0 mol%,the system cannot form glass.Thus,the fiber matrix glass component 34.9Bi₂O₃-35GeO₂-15Ga₂O₃-15Na₂O-0.1CeO₂ is selected.2.The spectral properties of Er³⁺doped and Er³⁺/Yb³⁺ co-doped bismuthate glass were investigated.It is found that when Er³⁺ is single-doped,the concentration of Er₂O₃ is 1.0mol%,the luminescence intensity reaches the maximum.When Er³⁺/Yb³⁺is co-doped,the incorporation of Yb³⁺ ions can effectively enhance the absorption of 980 nm band in the Er³⁺doped bismuthate glass sample.When the concentration of Er₂O₃ is 0.5 mol%and the concentration of Yb₂O₃ is 1.25 mol%,the observed fluorescence intensity of 1.5?m is the largest.In addition,it has also been observed that the incorporation of CeO₂ can suppress the up-conversion luminescence to some extent.3.The J-O strength parameters of Er³⁺/Yb³⁺co-doped bismuthate glass were calculated by J-O theory.The calculated?₂ is 8.41×10^-2020 cm²,?₄ is 2.48×10^-20 cm²,?₆ is 0.79×10^-20 cm²,the quality factor?is 3.139;the absorption cross section and stimulated emission cross section at 1.53?m are 0.60×10^-20 cm² and 0.82×10^-20 cm²,respectively.The probability of radiation transition is 266.58 S^-1 and the fluorescence lifetime is 3.75 ms at 1.53?m band.4.The double cladding structure design of glass fiber was carried out.And the Er³⁺/Yb³⁺ co-doped double cladding bismuthate glass fiber with a diameter of 300?m was drawn by the rod-tube combination method under the tuning control of a drawing temperature of 460±1?,a feed rate of 0.1-0.15 mm/min and a drawing speed of 1.034-1.551 m/min.5.A classical F-P cavity fiber laser was built by using the self-developed bismuthate glass fiber as the gain medium.Under the pump of 980 nm LD laser,a single-mode laser output with a center wavelength of 1535.4 nm was obtained.The obtained maximum laser output power was 93.64 mW,and the slope efficiency was 11.753%.