In this paper,a single-longitudinal-mode distributed Bragg reflector(DBR) fiber laser based on beat frequency interrogation is presented and its networking technique is also discussed.Due to the inherent fiber birefringence, the output laser consists of two orthogonal polarization modes highly sensitive to the change of temperature.Experimental results indicate that the beat frequency linearly decreases with the increase of temperature from 20 ℃ to 100 ℃, and the linearity is 0.999 81.Besides,it...