Self-Phase Modulation Phase Shift Calculator

Nonlinear Fiber Optics: Calculate nonlinear parameter ($\gamma$), effective interaction length ($L_{eff}$), and accumulated nonlinear B-integral phase shift ($\Phi_{NL}$).

Launch Power & Fiber Geometry

Peak Launch Power $P_{in}$ (dBm):

Fiber Span Length $L$ (km):

Effective Area $A_{eff}$ (µm²):

Fiber Loss $\alpha$ (dB/km):

Kerr Nonlinear Index

$n_2$ (10⁻²⁰ m²/W):

Wavelength $\lambda$ (nm):

Nonlinear Phase Shift & B-Integral

Nonlinear Phase Shift ($\Phi_{NL}$)

-- rad

In degrees: -- °

Nonlinear Coeff ($\gamma$)

-- W⁻¹·km⁻¹

Effective Length: -- km

Nonlinear Threshold (1.0 rad)

-- dBm

Kerr distortion status

Intensity at Core

-- MW/cm²

Peak Power: -- mW

Self-Phase Modulation (SPM) Physics:

• $\Phi_{NL} = \gamma P_{in} L_{eff}$. The Kerr effect modulates refractive index proportionally to signal intensity ($n = n_0 + n_2 I$).

• In coherent QAM systems, phase shifts $\Phi_{NL} > 1.0$ rad cause constellation rotation and phase noise (Gordon-Haus jitter).

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Self-Phase Modulation Phase Shift Calculator

Launch Power & Fiber Geometry

Kerr Nonlinear Index

Nonlinear Phase Shift & B-Integral

Frequently Asked Questions