设计了一种分离型光纤传感增敏结构,并联连接两个腔长相近的法布里-珀罗(F-P)腔。理论分析了此结构的增敏原理并制备了两组增敏结构。实验结果表明,增敏结构的压强灵敏度值由单F-P结构的4.85 nm/MPa提高到43.95 nm/MPa,温度灵敏度由单F-P腔的0.0675 nm/℃提高至0.40364 nm/℃,在相同温度下采用双腔结构可消除温度交叉敏感对测量结果的影响。此结构克服了集成式增敏结构的缺陷,在不影响原传感器结构的情况下提高了灵敏度,且可通过更换辅助腔来调节灵敏度,具有移植性好和交叉敏感小等优势。

A highly Tm-doped lead germanate glass fiber is developed using the rod-in-tube method. The ～2 μm laser beam quality of the fiber is ～1.5. The lead germanate composite fiber jumpers are homemade for all the fiber laser investigations. When core is pumped by a 1590 nm Yb/Er fiber laser, a maximum laser output of 313 mW is achieved at a 670 mW pump power, and the corresponding slope efficiency is ～52.8%. Moreover, by using a 2 cm-long lead germanate fiber as the gain medium, a 33 mW 1942 nm Tm laser is also demonstrated.

Enhanced 2.7 \mu m emission is obtained in Er3+/Tm3+ and Er3+/Ho3+ codoped ZBYA glasses. Absorption and emission spectra are tested to characterize the 2.7 \mu m emission properties of Er3+/Tm3+ and Er3+/Ho3+ doped ZBYA glasses and a reasonable energy transfer mechanism of 2.7 \mu m emission between Er3+ and Tm3+Ho3+) ion is proposed. Codoping of Tm3+ or Ho3+ significantly reduces the lifetime of the Er3+: 4I13/2 level due to the energy transfer of Er3+:4I13/2 →Tm3+:3F4 or Er3+:4I13/2 →Ho3+: 5I7. Thus, the 2.7 \mu m emission is strengthened and the 1.5 \mu m emission is decreased accordingly especially in the Er3+/Tm3+ sample. The upconversion effects between the Er3+/Tm3+ and Er3+/Ho3+ doped ZBYA glasses are different attribute to the different energy transfer efficiencies. Both of the two codoped samples possess nearly equal large emission cross section (16.6 \times 10-21 cm-2) around 2.7 \mu m. The results indicate that this Er3+/Tm3+ or Er3+/Ho3+ doped ZBYA glass has potential applications in 2.7 -m laser.

Emission enhancement at 2.7 mm is observed in Er3+/Pr3+-codoped germanate glasses when pumped by a 980-nm laser diode. Significant reductions in 1.5-mm emission and upconversion intensity indicate efficient energy transfer between Er3+ and Pr3+; the energy transfer efficiency is as high as 77.4%. The mechanisms of energy transfer are discussed in detail. The calculated emission cross-section of Er3+/Pr3+-codoped germanate glass is 8.44×10-21 cm2, which suggests that Er3+/Pr3+-codoped germanate glass can be used to achieve efficient 2.7-mm emission.