---
title: "Fiber Bragg Grating Wavelength calculator — AperiOptic"
description: "Bragg reflection wavelength from effective index and grating period. Free online optics calculator, with the formula and code snippets."
url: "https://aperioptic.com/calculators/fiber-bragg-grating-wavelength"
---

# Fiber Bragg Grating Wavelength calculator

Bragg reflection wavelength from effective index and grating period.

Category: [Fiber Optics](https://aperioptic.com/calculators)

Formula: `λB = 2 · neff · Λ`

## Inputs

| Input | Parameter | Unit | Default |
| --- | --- | --- | --- |
| n_eff | `neff` |  | 1.447 |
| Period Λ | `L` | nm | 535 |

## Result with the default inputs

- λB: 1548.29 nm

Open it with your own values: put each input in the address as a parameter, for example [`/calculators/fiber-bragg-grating-wavelength?neff=1.447`](https://aperioptic.com/calculators/fiber-bragg-grating-wavelength?neff=1.447). A unit other than the listed one goes in `<parameter>_unit`.

Read more: [Wikipedia: Fiber Bragg grating](https://en.wikipedia.org/wiki/Fiber_Bragg_grating)

[All optics calculators](https://aperioptic.com/calculators)

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The interactive page: https://aperioptic.com/calculators/fiber-bragg-grating-wavelength (AperiOptic runs in the browser; free, no account). Every page of the site as Markdown: https://aperioptic.com/llms.txt