# FBG Temperature Sensitivity and Multi-point Sensing Solutions for Wafer Temperature Measurement

**URL:** <https://forum.ofscn.net/t/fbg-temperature-sensitivity-and-multi-point-sensing-solutions-for-wafer-temperature-measurement/171>\
**Category:** Official Tech Inquiry & Product Q&A\
**Tags:** fbg-technology, wiki-fbg-tech, fbg-temp-sensor, fbg-interrogator\
**Created:** [January 6, 2026, 7:18am UTC](https://forum.ofscn.net/t/fbg-temperature-sensitivity-and-multi-point-sensing-solutions-for-wafer-temperature-measurement/171 "2026-01-06T07:18:01Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![chenshaoyang](https://forum.ofscn.net/letter_avatar_proxy/v4/letter/c/a8b319/32.png) [@chenshaoyang](https://forum.ofscn.net/u/chenshaoyang)\
**Post date:** [January 6, 2026, 7:18am UTC](https://forum.ofscn.net/t/fbg-temperature-sensitivity-and-multi-point-sensing-solutions-for-wafer-temperature-measurement/171/1 "2026-01-06T07:18:02Z")

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@ofscn_secretary

> [@光纤光栅灵敏度的问题？](https://forum.ofscn.net/t/topic/170):
>
> 我想用光纤光栅测温，想了解一下温度灵敏度是多少？

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<div class="post-metadata">

**Author:** ![ofscn\_secretary](https://forum.ofscn.net/letter_avatar_proxy/v4/letter/o/df788c/32.png) [@ofscn\_secretary](https://forum.ofscn.net/u/ofscn_secretary)\
**Post date:** [January 6, 2026, 7:18am UTC](https://forum.ofscn.net/t/fbg-temperature-sensitivity-and-multi-point-sensing-solutions-for-wafer-temperature-measurement/171/2 "2026-01-06T07:18:14Z")

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## FBG Temperature Sensitivity and Multi-point Sensing Solutions for Wafer Temperature Measurement

### Problem Description

A user inquired about the temperature sensitivity of Fiber Bragg Gratings (FBG) for temperature measurement. Subsequently, the user had a project requirement to measure temperature at 10 points on a 25 cm wafer, with temperatures not exceeding 100°C. The user also sought guidance on the necessary equipment beyond just the sensors.

### Technical Analysis

Fiber Bragg Grating (FBG) temperature measurement is based on the principle that the Bragg wavelength of the FBG drifts as temperature changes. This phenomenon arises from the thermo-optic effect and thermal expansion effect within the fiber material, leading to alterations in the effective refractive index and the grating period, which in turn causes the Bragg wavelength to shift.

Typically, the temperature sensitivity of a standard FBG is approximately **10-12 pm/℃**. This means that for every 1°C change in temperature, the grating’s central wavelength will drift by 10 to 12 picometers (pm). However, the precise value can be influenced by factors such as the fiber material, the grating fabrication process, and the sensor’s packaging method. For instance, OFSCN® sensors undergo precise temperature calibration at the factory, providing corresponding temperature-wavelength calibration formulas (often binomial) to ensure measurement accuracy.

For multi-point sensing, a single FBG sensor fiber can incorporate multiple grating elements (e.g., 10 sensing points). These multiple points can be efficiently monitored and read through a single channel of an FBG interrogator.

### Solution & Recommendation

1. **Sensor Selection:** For accurate temperature measurement at 10 points on a 25 cm wafer, where temperatures do not exceed 100°C, the **OFSCN® 100°C FBG Temperature Sensor** is recommended.

2. **Sensor Configuration for 10-point Wafer Measurement:** To optimally distribute 10 sensing points across a 25 cm wafer, the following preliminary planning is suggested:

3. **Interrogator Selection:** In addition to the sensor, a Fiber Bragg Grating (FBG) interrogator is essential to acquire the wavelength data from the sensor and convert it into meaningful temperature values.

### Recommended Product

OFSCN® 100°C FBG Temperature Sensor: [100℃ Fiber Bragg Grating Temperature Sensor - FBG Thermometer - Fiber Optic Grating Temperature Sensor - Customizable - Model Parameter Picture - Manufacturer Brand Price - DCYS - ofscn.net](https://www.ofscn.net/fbg-products/temperature-sensor-100.html)  
OFSCN® FBG Interrogator: [https://www.ofscn.net/fbg-products/fbg-interrogator.html](https://www.ofscn.net/fbg-products/fbg-interrogator.html)

(Source Discussion / 原帖讨论: [光纤光栅灵敏度的问题？](https://forum.ofscn.net/t/topic/170))