Abstract:To monitor the changes of external field information by using reflected polarization dependent loss of fiber grating and improve the measurement performance, the properties of reflected polarization dependent loss (RPDL) under the environmental conditions were studied. The relations of the changes of environmental conditions and the reflected polarization dependent loss were obtained by using coupled mode theory, and the effects of the variation of temperature, stress and pressure on the reflected polarization dependent loss spectrum were simulated. Numerical simulations show that the polarization dependent loss of fiber grating reflective light is insensitive to the changes of external temperature and stress, but obviously dependent on the changes of external pressure.