Research On The FBG Used In The Pressure Measurement Of Marine Exploration

Fiber Bragg grating (FBG) is a kind of wavelength modulated optical fiber passive device。 With the development of its production technology, FBG research has gradually become the focus. Compared with the traditional sensors, FBG sensors have lots of incomparable advantages, and have been widely used in the bridge structure monitoring, oil, electrical safety systems and other large projects. The mainly content of this paper as follows:Firstly, We review the development process of the FBG. Based on the optical coupling theory and the structure of the FBG, the principle of light travel in FBG is deduced. Then measuring principles on the temperature and strain are analyzed. At last, solutions to the problem of the temperature-pressure cross sensitive are discussed.Secondly, through the investigation of domestic and international FBG pressure sensors, the current popular modes of several stress sensitization are introduced, their advantages and disadvantages are analyzed.Thirdly, according to the theoretical research, the thin-walled cylindrical pressure sensor and the new diaphragm type pressure sensor are made. The pressure sensitivity of the thin-walled cylindrical pressure sensitivity is0.085nm/MPa with the measuring range of30MPa.Trough the exploration research on compression-sensitizing, we find a way to achieve a wide FBG compression. A novel pressure sensor based on the compression method and elastic diaphragm is invented. Its pressure sensitivity is as high as0.52nm/MPa, and its measuring range is30MPa.The overall performance of its sensitivity and measuring range is far beyond the existing pressure sensors.Finally, the prospect of fiber grating pressure sensor is envisaged.