Theoretical Study Of Pressure And Temperature Detected Simultaneously For Polarization-maintaining Fiber Sensor

The optical fiber sensor is a kind of new arisen sensors in the world, and polarization-maintaining optical fibers (PMF) also are the extensive application fibers. The optical fiber sensor based on polarized modes coupling has high sensitivity, can make the mature more exact in some peculiar occasions.The pressure and temperature are the environment factors that usually need to be measured. It is introduced the polarized modes coupling of polarization-maintaining fiber under pressure and educed the expression between polarized modes coupling coefficient and pressure. The fiber isn't sensitive to the temperature variety, but the coefficient of expansion of the metal is much bigger than the fiber, so make use of the stress produced by the expansion of the metal can measure the amount of variety of temperature. And it is gained the expression between polarized modes coupling coefficient and the amount of variety of temperature.It is simulated the gained theory and confirmed the direction angle between pressure and the axial when the polarized modes coupling coefficient is the biggest when other factors are fixed. It is also gotten the curve of polarized modes coupling coefficient and pressure, and the curve of stress and the amount of variety of temperature. And it is analyzed the curve of the polarized modes coupling coefficient and the amount of variety of temperature. It is also gained the approximate expression of polarized modes coupling coefficient with pressure and the amount of variety of temperature under considering linearity and the range of measure. It is gotten the Fiber Bragg Grating is relatively appropriate to measure pressure and the amount of variety of temperature simultaneously with the polarization-maintaining fiber under comparing some fiber gratings.