Fiber Optic Dispersion Calculator
Enter fiber type, length, dispersion coefficient, and spectral width to calculate pulse broadening and dispersion-limited bandwidth.
Fiber Parameters
Standard SMF at 1550 nm — positive value, normal dispersion regime.
DFB laser ≈ 0.1 nm · FP laser ≈ 1–5 nm · LED ≈ 30–60 nm
Enter parameters on the left and click Calculate.
Total Dispersion
—
ps/nm
Pulse Broadening
—
ps (RMS)
Max Bit Rate
—
NRZ limit
Calculation Details
Pulse Broadening vs. Bit Period
0%
25% limit
100%
Summary
Enter fiber type, length, dispersion coefficient, and spectral width to calculate pulse broadening and dispersion-limited bandwidth.
How it works
- Select fiber type: standard SMF (D ≈ 17 ps/nm·km at 1550 nm), DSF (D ≈ 0), NZDSF, or custom.
- Enter the fiber span length in kilometers.
- Enter the dispersion coefficient D in ps/nm·km (auto-filled for standard fiber types).
- Enter the source spectral width (FWHM) in nanometers — e.g., 0.1 nm for a DFB laser, 1–5 nm for an FP laser.
- Click Calculate to get total chromatic dispersion, RMS pulse broadening, and maximum dispersion-limited bit rate.
Use cases
- Estimate pulse broadening for a long-haul single-mode DWDM link before deploying dispersion compensation.
- Determine whether a Fabry-Perot laser source needs replacement with a DFB laser to meet bit-rate requirements.
- Size dispersion compensating fiber (DCF) or FBG modules for a given span.
- Compare G.652, G.653, and G.655 fiber performance at different wavelengths.
- Support optical communications coursework or lab calculations for fiber system design.
- Quickly sanity-check vendor dispersion specs against system rise-time budgets.
Frequently Asked Questions
Last updated: 2026-07-23 ·
Reviewed by Nham Vu