GVD broadening of chirp-free Gaussian: τ_out = τ_in√(1 + (L/L_D)²)

Agrawal 2019 Nonlinear Fiber Optics §3: an initially unchirped Gaussian pulse of 1/e-intensity half-width τ_in propagating through a linear dispersive medium (group-velocity dispersion β₂, GVD slope ω-derivative of group delay) broadens as…