Numerical Aperture of an Optical Fiber Calculator

This calculator computes the numerical aperture (NA) of an optical fiber based on its core refractive index and the refractive index of the surrounding medium.

Input Parameters

Calculation Results

Numerical Aperture (NA)

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NA = √(n₁² - n₂²)

Where:

n₁ = Core Refractive Index

n₂ = Surrounding Medium Refractive Index

Numerical Aperture of an Optical Fiber Calculator Usage Guide

Learn how to use the Numerical Aperture of an Optical Fiber Calculator and its working principles

What is Numerical Aperture (NA)?

The numerical aperture of an optical fiber is a dimensionless number that characterizes the range of angles over which light can be accepted into the fiber and propagate along its core. It is defined as:

NA = √(n₁² - n₂²)

Where:

  • n₁ = Refractive index of the fiber core
  • n₂ = Refractive index of the surrounding medium (usually air, n₂ ≈ 1.0)

How to Use This Calculator

  1. Enter the refractive index of the fiber core (n₁). Typical values range from 1.45 to 1.46 for silica fibers.
  2. Enter the refractive index of the surrounding medium (n₂). For air, use 1.0.
  3. Click the "Calculate" button to compute the numerical aperture.
  4. The result will be displayed in the NA field.

Practical Applications

The numerical aperture is crucial for determining the light-gathering ability of an optical fiber. A higher NA allows more light to enter the fiber but can also increase fiber loss. It also affects the resolution of imaging systems using optical fibers.