---
title: "Fiber Splice Loss calculator — AperiOptic"
description: "Insertion loss from transverse, longitudinal and angular SMF misalignment. Free online optics calculator, with the formula and code snippets."
url: "https://aperioptic.com/calculators/fiber-splice-loss"
---

# Fiber Splice Loss calculator

Insertion loss from transverse, longitudinal and angular SMF misalignment.

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

Formula: `Lossdb from gaussian-mode overlap of MFD`

## Inputs

| Input | Parameter | Unit | Default |
| --- | --- | --- | --- |
| Mode field radius | `w` | µm | 5.2 |
| Transverse offset | `x` | µm | 1 |
| Long. gap | `z` | µm | 5 |
| Angular tilt | `th` | deg | 0.5 |
| λ | `lam` | nm | 1550 |

## Result with the default inputs

- Transmission: 95.359 %
- Loss: 0.206 dB

Open it with your own values: put each input in the address as a parameter, for example [`/calculators/fiber-splice-loss?w=5.2`](https://aperioptic.com/calculators/fiber-splice-loss?w=5.2). A unit other than the listed one goes in `<parameter>_unit`.

Read more: [Wikipedia: Fusion splicing](https://en.wikipedia.org/wiki/Fusion_splicing)

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

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