Principle of North Asia Professional Temperature Measuring Optical Cable

The optical cable measures temperature by detecting changes in light scattering or radiation along the fiber, using distributed sensing techniques such as Raman or Brillouin scattering.

Working Principle

The North Asia Professional Temperature Measuring Optical Cable operates on the distributed temperature sensing (DTS) principle, where a standard fiber optic cable acts as a continuous temperature sensor along its entire length. A pulsed laser is sent through the fiber, and interactions between the light and the fiber's glass structure cause a small fraction of light to scatter back. The time delay of the backscattered light is analyzed to determine the location of temperature changes, similar to radar echo analysis, a method known as Optical Time Domain Reflectometry (OTDR). Alternatively, Optical Frequency Domain Reflectometry (OFDR) can be used, which analyzes the backscatter signal in the frequency domain for high-resolution measurements .

Temperature Measurement Mechanisms

1. Raman Scattering: The fiber detects two Raman components, Stokes and anti-Stokes. The intensity ratio between these signals depends on the local temperature, allowing precise calculation of temperature along the fiber .
2. Brillouin Scattering: The Brillouin frequency shift is linearly related to temperature and strain. By measuring this shift, the system can estimate temperature at each point along the fiber .
3. Blackbody Radiation: Some high-temperature optical cables use a blackbody cavity at the measurement point. Thermal radiation emitted by the cavity is transmitted through the fiber and analyzed according to Planck's law, providing temperature information for extreme heat environments .

Advantages

• Continuous monitoring: Provides a spatially resolved temperature profile along the entire cable, not just at discrete points .
• High accuracy and resolution: Typical spatial resolution can reach 1 meter, with temperature accuracy within ±1°C and sensing resolution down to 0.01°C .
• Immunity to electromagnetic interference: Ideal for high-voltage or industrial environments where traditional electrical sensors fail .
• Long-distance capability: Can monitor assets over tens of kilometers using standard telecom fiber .
• Safety and reliability: Low optical pulse power and proprietary signal processing reduce risks in hazardous areas .

Applications

These optical cables are widely used for power cable monitoring, pipelines, tunnels, and high-voltage submarine cables, where they provide real-time temperature profiles to prevent overheating, assess insulation condition, and optimize operational safety . In summary, the North Asia Professional Temperature Measuring Optical Cable leverages fiber-optic distributed sensing to provide accurate, continuous, and safe temperature monitoring over long distances, using advanced optical scattering and radiation principles.