Optical Fiber Numerical Aperture & V-Number Calculator

Determine fiber Numerical Aperture (NA), acceptance cone angle, normalized frequency (V-number), single-mode cutoff condition, and guided LP mode capacity.

Fiber Parameters & Refractive Indices

Core Index (n₁):

Cladding Index (n₂):

Core Radius a (µm): Standard SMF-28 core radius ~4.1 µm

Wavelength λ (nm): Telecom bands: 1310 nm / 1550 nm

Standard Fiber Preset:

Waveguide Propagation & Modes

Numerical Aperture (NA)

V-Number (Norm. Frequency)

Acceptance Half-Angle

Critical TIR Angle θ_c

Guided Mode Count (M)

Cutoff Wavelength & Mode Field Diameter

Single-mode Cutoff λ_c: -- nm | Petermann II MFD: -- µm

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Optical Fiber Numerical Aperture & V-Number Calculator

Fiber Parameters & Refractive Indices

Waveguide Propagation & Modes

Frequently Asked Questions