通过化学腐蚀辅助飞秒激光改性的方法, 在普通单模光纤(SMF-28)上加工了一种V槽型全光纤马赫泽德尔干涉仪(MZI)传感器件。该器件具有良好的光谱特性, 条纹可见度达到6 dB; 此外, 还具有优异的折射率和温度传感特性。当外界折射率在1.33～1.45变化时, 线性拟合得到其灵敏度高达8 225 nm/RIU, 线性度高达0.997; 在水中, 当温度由25 ℃变化到60 ℃时, 其温度灵敏度高达1.805 nm/℃。研究表明, 该传感器结构紧凑, 易于加工制造, 并且具有极高的折射率灵敏度, 特别适用于溶液折射率检测。

A fiber in-line Mach-Zehnder interferometer (MZI) with V-shape micro-cavity fabricated by femtosecond laser micromachining and chemical etching method in SMF-28 is proposed.The MZI has showngood spectral characteristics and the fringe visibility of 6dB is observed. Moreover, it has exhibited excellent refractive index and temperature sensing properties. An extremely high refractive index sensitivity of 8 225 nm/RIU with the linearity of 0.997 in the range of 1.33～1.45 is obtained. At the same time, its temperature sensitivity is as high as 1.805 nm/℃ in water in the range from 25 ℃ to 60 ℃. It has demonstrated that the MZI sensor is especially suitable for the refractive index measurement because of its compact size, easy manufacturing and extra-high refractive index sensitivity.