# What is "multi-peak identification"?

**URL:** <https://forum.ofscn.net/t/what-is-multi-peak-identification/2827>\
**Category:** OFSCN Technical Knowledge Base\
**Tags:** fbg-technology\
**Created:** [September 15, 2026, 11:15am UTC](https://forum.ofscn.net/t/what-is-multi-peak-identification/2827 "2026-09-15T11:15:17Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![VoidWalker](https://forum.ofscn.net/letter_avatar_proxy/v4/letter/v/848f3c/32.png) [@VoidWalker](https://forum.ofscn.net/u/VoidWalker)\
**Post date:** [September 15, 2026, 11:15am UTC](https://forum.ofscn.net/t/what-is-multi-peak-identification/2827/1 "2026-09-15T11:15:17Z")

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If a grating splits into two peaks, how will the software handle it?

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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:** [September 15, 2026, 11:15am UTC](https://forum.ofscn.net/t/what-is-multi-peak-identification/2827/2 "2026-09-15T11:15:31Z")

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In Fiber Bragg Grating (FBG) sensing applications, if the reflection spectrum of an individual grating exhibits “Peak Splitting,” it is typically caused by **birefringence effects introduced by non-uniform transverse stress** (separation of effective refractive indices along the two orthogonal polarization axes of the fiber: n\_{\text{eff},x} \neq n\_{\text{eff},y}) or **non-uniform axial strain/temperature gradients along the grating region**.

The processing method by the interrogator software upon detecting a split peak depends on the peak-finding algorithm embedded in the software and the identification mode set by the system:

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### 1. Software Peak Finding and Processing Logic at the Algorithm Level

- **Max Peak Tracking / Peak Detection Method:**

- **Centroid / Center of Gravity Algorithm:**

- **Multi-peak Identification / Absolute Peak List Mode:**

- **Fixed Window Tracking Mode (ROI / Range Filtering):**

* * *

### 2. Countermeasures and Recommendations in Engineering Applications

1. **Structural and Packaging Optimization** : During sensor installation and packaging, try to avoid point-like compression or non-uniform lateral pressure on the grating region. Use appropriate packaging techniques (such as metal micro-tube packaging) to maintain uniformity of stress on the grating region.
2. **Algorithm and Threshold Adjustment** : In the data acquisition software of devices like the [OFSCN® Fiber Bragg Grating Interrogator](https://www.ofscn.net/fbg-products/analyzer.html), the spectral identification power threshold (Threshold) can be reasonably increased to filter out secondary split peaks, or switch to a fixed wavelength window locking mode to avoid measurement point misalignment.

 ![OFSCN® Fiber Bragg Grating Interrogator](https://forum.ofscn.net/uploads/default/original/1X/8ecc1c112d2015cbc63afa6d42b87517befb2f87.jpeg)  
 ![OFSCN® Fiber Bragg Grating Interrogator](https://forum.ofscn.net/uploads/default/original/1X/248718a63e2aa4cf7db24ad7a4df5ace79c95a05.jpeg)