基于光纤 Bragg 光栅的波长变化受光纤纤芯的有效折射率和光栅周期的影响，通过测量光纤 Bragg 光栅的反射波长的变化，可以探知环境物理量的变化。在假设压力场和轴向应力场保持恒定的基础上得到的温度传感模型，结合三峡大坝坝前水温监测的要求，建议采用温度与波长的二次式关系。其标定结果能够满足要求，并且监测的结果较好。

The wavelength variation of Fiber Bragg Grating (FBG) is affected by the effective refraction ratio and fiber Bragg grating period . From measuring the change of reflected wavelength of FBG, we can ascertain the change of environment. We suppose that with pressure field and the axial stress field being kept constant, then a temperature sensing model is set up, and in combination with demand of measuring the water temperature in front of the Three Gorges Dam , we suggest using the quadratic relationship of temperature and wavelength. The calibration results can meet the requirements, and the monitoring results are good.