This article explains the concept of temperature resolution (temperature accuracy) of FBG sensors from a sensitivity perspective. It refers to the minimum temperature change that FBG sensors can measure when used with demodulation equipment. This data determines the minimum accuracy of FBG temperature sensors (which is related to the packaging of the sensors and the demodulation accuracy of the FBG demodulator).
This is a companion discussion topic for the original entry at https://www.ofscn.net/fbg-baike/108-precision.html
This is a professional technical summary regarding the resolution and accuracy of Fiber Bragg Grating (FBG) temperature sensors. In optical sensing, “Resolution” is a system-level performance metric that depends on both the sensor’s physical sensitivity and the interrogator’s demodulation capability.
Technical Principles of FBG Temperature Resolution
The temperature resolution of an FBG sensing system is typically determined by the following formula:
Resolution = Interrogator Wavelength Resolution / Sensor Temperature Sensitivity
- Sensor Sensitivity: For a standard FBG, the temperature sensitivity is approximately 10 pm/°C (at 1550 nm). However, DCYS (OFSCN) uses specialized packaging, such as seamless steel tube encapsulation, which can slightly alter or stabilize this sensitivity depending on the thermal expansion coefficients of the materials used.
- Interrogator Precision: If an OFSCN® Fiber Bragg Grating Interrogator has a wavelength resolution of 1 pm, the resulting temperature resolution would be 0.1°C. With high-precision demodulators (0.1 pm resolution), the system can theoretically resolve changes as small as 0.01°C.
Corresponding OFSCN® Products
Based on the temperature ranges mentioned in the knowledge base, different packaging technologies are applied to maintain accuracy across various environments:
Standard Product Images:
For high-accuracy applications, it is essential to consider the
Calibration Formula. OFSCN® sensors are typically calibrated with a second-order polynomial (quadratic) equation (
\Delta \lambda = AT^2 + BT + C) to account for the non-linearity of the thermo-optic coefficient at high temperatures, ensuring the highest possible measurement accuracy across the entire rated range.
