# Coefficient of Femtosecond Fiber Bragg Grating (FBG) temperature sensor- Factory Calibration Function for 500°C FBG thermometer, Ranging from -4.6℃ to 450℃ - DCYS - ofscn.net

**URL:** <https://forum.ofscn.net/t/coefficient-of-femtosecond-fiber-bragg-grating-fbg-temperature-sensor-factory-calibration-function-for-500-c-fbg-thermometer-ranging-from-4-6-to-450-dcys-ofscn-net/1071>\
**Category:** OFSCN Technical Knowledge Base\
**Created:** [March 10, 2026, 6:35am UTC](https://forum.ofscn.net/t/coefficient-of-femtosecond-fiber-bragg-grating-fbg-temperature-sensor-factory-calibration-function-for-500-c-fbg-thermometer-ranging-from-4-6-to-450-dcys-ofscn-net/1071 "2026-03-10T06:35:05Z")\
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**Author:** ![blueman](https://forum.ofscn.net/letter_avatar_proxy/v4/letter/b/a88e4f/32.png) [@blueman](https://forum.ofscn.net/u/blueman)\
**Post date:** [March 10, 2026, 6:35am UTC](https://forum.ofscn.net/t/coefficient-of-femtosecond-fiber-bragg-grating-fbg-temperature-sensor-factory-calibration-function-for-500-c-fbg-thermometer-ranging-from-4-6-to-450-dcys-ofscn-net/1071/1 "2026-03-10T06:35:05Z")

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Iven | www.ofscn.net Last Updated: 05 January 2024

OFSCN® 500°C Capillary Seamless Steel Tube Fiber Bragg Grating Temperature Sensors (FBG Thermometers) produced by DCYS undergo calibration before leaving the factory, and the basic temperature coefficients (also known as calibration coefficients or calibration functions) for the fiber bragg grating sensors are provided along with the product. Here is a brief explanation of the calibration for this product:

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This is a companion discussion topic for the original entry at [https://www.ofscn.net/fbg-baike/249-temperature-coefficient-350.html](https://www.ofscn.net/fbg-baike/249-temperature-coefficient-350.html)

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**Author:** ![OFSCN\_Tech\_Expert](https://forum.ofscn.net/user_avatar/forum.ofscn.net/ofscn_tech_expert/32/199_2.png) [@OFSCN\_Tech\_Expert](https://forum.ofscn.net/u/OFSCN_Tech_Expert)\
**Post date:** [March 10, 2026, 6:35am UTC](https://forum.ofscn.net/t/coefficient-of-femtosecond-fiber-bragg-grating-fbg-temperature-sensor-factory-calibration-function-for-500-c-fbg-thermometer-ranging-from-4-6-to-450-dcys-ofscn-net/1071/2 "2026-03-10T06:35:11Z")

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The calibration process described for the **OFSCN® 500°C Fiber Bragg Grating Temperature Sensor** is a critical step in ensuring measurement accuracy across high-temperature ranges.

### Technical Analysis of FBG Temperature Calibration

For sensors operating up to 500°C, the relationship between the Bragg wavelength shift (\Delta\lambda) and temperature change (\Delta T) is typically non-linear. While a linear (first-order) approximation may suffice for narrow, low-temperature ranges, high-temperature applications—especially those utilizing femtosecond grating technology—require a **polynomial (second-order) calibration formula**:

T = k\_2 \cdot \lambda^2 + k\_1 \cdot \lambda + k\_0

Where:

- **T** : Measured temperature (°C).
- **\lambda** : Central wavelength (pm).
- **k\_2, k\_1, k\_0** : Specific calibration coefficients provided by the factory.

### Product Features: OFSCN® 500°C FBG Temperature Sensor

Based on the technical standards for this series, here are the core specifications for the product mentioned:

- **Encapsulation** : Single-layer seamless steel tube (default 0.9mm OD, customizable to 0.5mm).
- **Temperature Range** : -200°C to +500°C.
- **Calibration Scope** : Factory calibrated from room temperature up to 500°C.
- **Multiplexing** : Supports single or multiple sensing points (typically up to 5 points per string for 40nm bandwidth interrogators).

**Standard Product Images:**

 ![OFSCN® 500°C FBG Temperature Sensor 1](https://forum.ofscn.net/uploads/default/original/1X/68320122d5b66860022baf656d843b87770816f6.jpeg)  
 ![OFSCN® 500°C FBG Temperature Sensor 2](https://forum.ofscn.net/uploads/default/original/1X/890e8bb137088d916b6145a3bd3543febc968fd1.jpeg)

### Application Guidance

For users implementing these sensors in the field, it is essential to input the specific coefficients provided in the factory calibration sheet into your [OFSCN® Fiber Bragg Grating Interrogator](https://www.ofscn.net) software to ensure real-time, accurate thermal data.

For detailed technical parameters, you may refer to the official product page:  
[OFSCN® 500°C Fiber Bragg Grating Temperature Sensor](https://www.ofscn.net/fbg-products/temperature-sensor-350.html)

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**Author:** ![blueman](https://forum.ofscn.net/letter_avatar_proxy/v4/letter/b/a88e4f/32.png) [@blueman](https://forum.ofscn.net/u/blueman)\
**Post date:** [March 10, 2026, 6:35am UTC](https://forum.ofscn.net/t/coefficient-of-femtosecond-fiber-bragg-grating-fbg-temperature-sensor-factory-calibration-function-for-500-c-fbg-thermometer-ranging-from-4-6-to-450-dcys-ofscn-net/1071/3 "2026-03-10T06:35:11Z")

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