DTS uses the temperature-dependent Raman anti-Stokes/Stokes relationship to calculate temperature at successive locations along the cable. The result supports hotspot investigation, linear heat detection and thermal-operating decisions.
How temperature changes the light — Raman scattering
Returning Raman light has two bands: Stokes and anti-Stokes. Their calibrated ratio is strongly temperature-sensitive and reduces common-mode intensity effects. It is not fully independent of attenuation: differential loss between the bands, bends, splices and cable transitions must be characterised or compensated.
S ≈0.096 %/K
Schematic. The displayed relative sensitivities are local values around 20 °C, not constants over the slider’s full range. Calibration converts the anti-Stokes/Stokes relationship into temperature. Differential attenuation is system- and route-specific; suitable double-ended acquisition can compensate spatially varying loss.
The temperature profile along the cable
A calibrated DTS returns a temperature profile at locations defined by the selected spatial resolution and sampling configuration. A local rise at a cable joint or tunnel section can be located for investigation; operational thresholds and response logic are engineered for the application.
Where DTS creates operational value
Power cables
Detect local heating and provide measured temperature to dynamic cable-rating or RTTR software. Ampacity is calculated with an appropriate thermal model; DTS alone does not calculate it.
Tunnels and linear heat detection
Position-resolved heat detection with response time, zoning and alarm logic selected for the tunnel design and applicable requirements.
Industrial installations
Temperature profiles for pipelines, tanks, conveyors and processes where isolated point sensors cannot show the full thermal pattern.
DTS at INTERLAB
INTERLAB supplies DTS platforms from the Luna Innovations sensing group, including LIOS and Silixa:
* Manufacturer maxima refer to specific products, operating modes and channel counts; they are not necessarily available simultaneously. Coverage, spatial granularity, measurement rate and uncertainty are confirmed for the selected configuration and application conditions.
The 70 °C threshold in the animation is illustrative, not a design recommendation. DTS temperature is derived from calibrated Raman measurements; local differential attenuation may require compensation or double-ended acquisition.
For selection, provide route length, one- or two-ended access, cable type, temperature range, required spatial granularity, response time and whether the objective is LHD, power-cable rating or process monitoring.
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Frequently asked questions
Why measure the anti-Stokes/Stokes ratio instead of intensity alone?
What range and spatial performance can I expect?
Can DTS and DAS share one cable or one fiber?
What information is needed to select a DTS system?
Need continuous temperature visibility along a route?
Send the route length, topology, temperature range, response requirement and application — power cable, LHD or process monitoring. We will match the LIOS or Silixa system and sensing cable to the task.
Request a DTS configuration →