Abstract: The structure design of a fiber Bragg grating (FBG) sensor based on the C-shaped elastic tube has been put forward. The tuning of the FBG reflected wave length is carried out by using the excess pressure in the elastic tube for making the free end of the said tube produce displacement, or making the surface of the said tube produce stress. The linear elationship of FBG reflected wavelength variation against both the pressure and the free end displacement has been obtained. In a ressure range of 1～6MPa, the relationship between FBG reflected wave length and pressure or displacement is a linear characteristic, with the sensitivity of the pressure and displacement sensor reaching 0. 0305nm/MPa and 0. 0359nm/mm respec
tively, with the linear tuning range being 0.183nm and 0.215nm respectively, and with the wave length resolving capability being 3.05pm and 0.718pm respectively.

Key words: fiber Bragg gratings(FBG), C-Shaped elastic tube, optic fiber sensing