Optical Fiber Chromatic Dispersion Calculator

Optical telecommunications & photonics: Calculate chromatic dispersion parameter ($D$), group velocity dispersion ($\beta_2$), pulse temporal broadening ($\Delta \tau$), and dispersion-limited transmission distance & bit rate.

Fiber & Source Parameters

Fiber Standard Preset:

Operating Wavelength $\lambda$ (nm):

Zero-Disp. Wavelength $\lambda_0$ (nm):

Zero-Disp. Slope $S_0$ (ps/(nm²·km)):

Fiber Link Length $L$ (km):

Source Linewidth $\Delta \lambda$ (nm):

Initial Pulse FWHM $\tau_0$ (ps):

Data Transmission Rate $B$ (Gbps):

Dispersion & Broadening Results

Dispersion Parameter $D$

ps/(nm·km)

GVD Parameter $\beta_2$

$\text{ps}^2/\text{km}$

Pulse Broadening $\Delta \tau$

ps (temporal spread)

Output Pulse Width $\tau_{out}$

ps (FWHM)

Max Reach $L_{max}$ (@ $B$)

km (NRZ 1-dB penalty limit)

Dispersion Length $L_D$

km (Gaussian pulse)

Pulse Temporal Broadening Waveform

Optical pulses broaden monotonically with link length due to group velocity dispersion ($D > 0$, anomalous regime @ 1550 nm).

Dispersion Physics & Telecomm Limits

Chromatic dispersion is the sum of material dispersion ($D_M$) and waveguide dispersion ($D_W$). In standard single-mode fibers (ITU-T G.652), the dispersion parameter $D(\lambda)$ is modeled by the Sellmeier derivative:

          $$D(\lambda) = \frac{S_0}{4} \left( \lambda - \frac{\lambda_0^4}{\lambda^3} \right) \quad [\text{ps}/(\text{nm}\cdot\text{km})]$$
          $$\beta_2 = -\frac{\lambda^2}{2 \pi c} D \quad [\text{ps}^2/\text{km}]$$
        

For non-return-to-zero (NRZ) on-off keying, inter-symbol interference (ISI) limits the bit rate-distance product to $B^2 |\beta_2| L \lesssim 0.04$ (or $B \cdot \Delta \tau \le 0.25$). Beyond this distance, electronic dispersion compensation (EDC) or optical dispersion compensating fiber (DCF) is mandatory.

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Optical Fiber Chromatic Dispersion Calculator

Fiber & Source Parameters

Dispersion & Broadening Results

Pulse Temporal Broadening Waveform

Dispersion Physics & Telecomm Limits

Frequently Asked Questions