High-power wavelength-tunable cladding-pumped rare-earth-doped silica fiber lasers

We describe the design and performance of cladding-pumped silica fiber lasers with high continuous-wave output powers and broad wavelength tunability in the 1, 1.5, and 2 μm spectral ranges. An ytterbium-doped fiber laser was tuned via wavelength dependent feedback provided by an external cavity containing a diffraction grating from 1027 to 1105 nm at multi-watt power levels. Similarly, high output power and wide wavelength tunability from 1540 to 1600 nm and from 1860 to 2090 nm at multi-watt output power levels has been achieved in Er-Yb co-doped and Tm-doped silica fiber lasers, respectively. A neodymium doped fiber laser was tuned from 1057 to 1118 nm at a lower power level. Limiting factors and the prospects for further improvements in performance are considered.     

单模光纤拉伸器分布式双折射特性实验研究

在偏振敏感光纤系统中,光纤双折射是重要的参 量。基于压电陶瓷的单模光纤(single-mode fiber,SMF)拉伸器是光纤系统中引入应变、光程或 相位变化等常用的器件,而少有人关注过光纤拉伸器引入的双折射特性。本文提出基于分布 式偏振分析的SMF拉伸器双 折射特性表征方法,结合全穆勒矩阵分析和光频域反射仪技术,可以得到SMF拉伸器缠 绕光纤的分布式双折射特性。实 验得到:在光纤拉伸器使用过程中,光纤双折射随驱动电压增大而增加;当光纤拉伸器缠绕 光纤表面不平整时,可引入更高 的基底双折射,且在施加驱动电压时,基底双折射增加更加明显;设计合适的拉伸机构和光 纤缠绕方法,能有效地避免光纤拉 伸器使用过程中双折射的改变,但可能会引入较强的基底双折射。本文研究结果对于在偏振 敏感光纤系统中使用光纤拉伸器时系统性能的评估及优化具有指导意义。     

Liquid pressure sensing system based on distributed polarization crosstalk analysis in polarization maintaining fiber

A novel quasi-distributed liquid pressure sensing system based on distributed polarization crosstalk analysis (DPXA) in polarization maintaining fiber (PMF) is proposed and demonstrated. We design a special structure of liquid pressure sensing units and invent a corresponding nonlinear calibration method. Five sensing units deployed on a sensing tape can effectively transform the liquid pressure into the transverse-force applied on the sensing PMF, and the induced polarization crosstalk can be measured and located by the DPXA system, so as to further establish the relationship between liquid pressure and crosstalk through the nonlinear calibration method. The liquid pressure sensing system has good sensitivity and high repeatability, and a maximal measurement relative error of 8.96% is measured for the five sensing units, which can be much improved by optimizing the packaging of sensing units. We believe our sensing system will find great applications in the field of engineering liquid pressure sensing.