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.