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.