---
title: "Prism Pair Pulse Compression calculator — AperiOptic"
description: "GDD of a Brewster prism pair, per pass: angular-dispersion term (−) plus the glass in the beam (+). Fused silica at 800 nm by default. Free online optics calculator, with the formula and code snippets."
url: "https://aperioptic.com/calculators/prism-pair-pulse-compression"
---

# Prism Pair Pulse Compression calculator

GDD of a Brewster prism pair, per pass: angular-dispersion term (−) plus the glass in the beam (+). Fused silica at 800 nm by default.

Category: [Laser & Ultrafast](https://aperioptic.com/calculators)

Formula: `GDD = (λ³/2πc²)·[Lglass·d²n/dλ² − 4·L·(dn/dλ)²]`

## Inputs

| Input | Parameter | Unit | Default |
| --- | --- | --- | --- |
| Wavelength | `lam` | nm | 800 |
| Apex separation | `L` | cm | 50 |
| dn/dλ (1/µm) | `dn` |  | -0.01728 |
| d²n/dλ² (1/µm²) | `d2n` |  | 0.03988 |
| Glass path | `Lglass` | mm | 5 |

## Result with the default inputs

- GDD per pass: -360.67 fs²
- GDD double pass: -721.3399 fs²
- Angular term: -541.4597 fs²
- Glass term: 180.7898 fs²

Open it with your own values: put each input in the address as a parameter, for example [`/calculators/prism-pair-pulse-compression?lam=800`](https://aperioptic.com/calculators/prism-pair-pulse-compression?lam=800). A unit other than the listed one goes in `<parameter>_unit`.

Read more: [Wikipedia: Chirped pulse amplification](https://en.wikipedia.org/wiki/Chirped_pulse_amplification)

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

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