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Fiber Optic Numerical Aperture and Acceptance Angle Calculator

NA = √(n₁² − n₂²); θ_accept = arcsin(NA).

Calculates the Numerical Aperture (NA) and maximum acceptance angle of an optical fiber from the refractive indices of core and cladding.

Nadia Almasri By Nadia Almasri
Published Last reviewed 1 min read

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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

NA = sqrt(n_core² − n_clad²); θ (°) = arcsin(NA) × 180/π

In depth

Calculates the Numerical Aperture (NA) and maximum acceptance angle of an optical fiber from the refractive indices of core and cladding.