除掉光纤布拉格光栅的包层,可以使它的布拉格波长对外界环境的折射率变化敏感。采用氢氟酸腐蚀掉光纤布拉格光栅的包层,获得了直径约为6μm的布拉格光栅。实验研究了布拉格波长对化学溶液的浓度敏感性特征,结果表明:采用10 pm分辨率的光谱仪,丙二醇溶液在低浓度时的浓度分辨率为0.7%,在高浓度时的分辨率为0.32%;糖溶液在低浓度时的分辨率为0.55%,高浓度时为0.1%。采用商用的分辨率为1 pm的高精度波长解调系统,它们的分辨率可以提高一个数量级。

Bragg wavelength sensitivity to the refractive index of the ambient media can be realized by etching out the cladding of fiber Bragg grating.A fiber Bragg grating with the diameter of 6 μm is abtained through hydrofluoric(HF) acid etching.Bragg wavelength sensitivity to chemical solutions is experimentally investigated.With an optical spectrum analyzer to detect the wavelength shift,the concentration resolutions of propylene glycol solutions are 0.7% and 0.32% at low and high concentrations,respectively.For sugar solutions,concentration resolutions are 0.55% and 0.1% respectively.In addition,the concentration resolutions can be improved an order of magnitude with wavelength interrogation module of 1 pm resolution.