Distributed Temperature Sensing (DTS) systems provide temperature information for accurate thermal monitoring, fire detection, and condition assessment by utilizing standard fiber optic cables. These fiber optic systems precisely measure the temperature profile of an asset by interpreting the interaction of light with the glass structure of the optical fiber. Monitoring an asset along the fiber optic cable in real time supplies the information needed to trigger or adjust preventive or corrective actions for assets such as power cables, pipelines, or tunnels.
Contact NowDistributed Temperature Sensing (DTS) utilizes standard optical fibers, typically spanning dozens of kilometers, to serve as linear temperature sensors. This approach provides a spatially well-resolved temperature profile along the entire length of the sensor cable, with a resolution down to one meter.
DTS technology is based on either Raman or Brillouin optical scattering. A laser pulse is periodically launched into the fiber, from which a small fraction is scattered back due to the interaction of the light with the glass structure. The fraction that is scattered back to the interrogator is continuously analyzed. The position of the temperature reading is derived from the arrival time of the returning light, analogous to radar echo analysis. This method is referred to as Optical Time Domain Reflectometry (OTDR). Technically slightly different, but mathematically equivalent is the Optical Frequency Domain Reflectometry (ODFR). For covering long distance with best signal to noise ratio, the time domain (OTDR) approach shows advantages due to lower shot noise.
In DTS systems based on Raman scattering, two different Raman components are individually analysed, the Stokes and the anti-Stokes band. The intensity ratio between both signals depends on the local temperature and is used to calculate the temperature along the optical fiber.