超短线性腔是实现单频激光稳定输出的最简单的结构,针对石英玻璃光纤掺杂离子浓度低、输出功率小的缺点,选择对稀土离子具有较高溶解度的磷酸盐玻璃作为增益介质,研究了Yb3+掺杂磷酸盐玻璃(P2O5-B2O3-K2O-BaO-Al2O3-Nb2O5-Sb2O3)的光谱特性,解决了Yb2O3高浓度掺杂和提高Yb3+荧光寿命的问题。实验表明磷酸盐玻璃对Yb2O3溶解度摩尔分数可达6%(质量分数为15.5%);通过除水技术,Yb3+离子2F5/2能级的寿命达到1.84 ms。在此基础上采用管棒法拉制出了磷酸盐玻璃单模光纤,通过光栅选频,利用1.4 cm光纤实现了中心波长1063.5 nm,功率51.6 mW的单频激光输出。

Ultra-short linear cavity is the simplest configuration to achieve stable single-frequency laser output. In order to increase the rare-earth doping concentration we choose phosphate glass as the laser gain medium. The spectroscopic properties of heavily Yb3+-doped phosphate glasses(P2O5-B2O3-K2O-BaO-Al2O3-Nb2O5-Sb2O3) have been investigated for developing 1064 nm single-frequency fiber laser. The experimental results show that the molar fraction solubility of Yb2O3 in this phosphate glass system is up to 6% (mass fraction 15.5%). Based on the reaction atmosphere process,the OH- groups can be removed effectively and the fluorescence lifetime of the 2F5/2 state of Yb3+ ion in phosphate glass reaches 1.84 ms. The Yb3+-doped phosphate glass fiber has been drawn by the rod-in-tube technique. A continuous-wave single frequency laser with 51.6 mW laser output at 1063.5 nm is achieved in a 1.4 cm phosphate glass fiber through a narrow bandwidth Bragg grating.