DTS(Distributed Temperature Sensing) uses the Raman effect to measure temperature. The optical laser pulse sent through the fiber causes some scattered light to be reflected on the transmitter side, where the information is analyzed on the Raman principle and the optical time domain reflection (OTDR) localization principle. As the laser pulse propagates through the fiber, several types of scattering are generated, among which the Raman is sensitive to temperature variations, the higher the temperature, the higher the intensity of the reflected light.

The intensity of Raman scattering measures the temperature along the fiber. The Raman anti-Stokes signal changes its amplitude significantly with temperature; the Raman-Stokes signal is relatively stable.