Generating few-cycle energetic and broadband mid-IR pulses is an urgent current challenge in nonlinear optics. Cascaded second-harmonic generation (SHG) gives access to an ultrafast and octave-spanning self-defocusing nonlinearity: when ΔkL >> 2π the pump experiences a Kerr-like nonlinear index change Δn = ncascI, where ncase ∝ −d2eff/Δk, and deff is the effective quadratic nonlinearity. Due to competing material nonlinearities nKerr the total nonlinear refractive is ncubic = ncasc + nKerr. Interestingly ncubic can become negative (self-defocusing), elegantly avoiding self-focusing problems, and making it possible to excite solitons with normal dispersion [1].