A solid-core photonic-crystal fiber (PCF) with an effective mode area of $20\mu {\mathrm{m}}^2$ is used to demonstrate the generation of sub- $100\text{-}\mathrm{kW}$ , $30–70\mathrm{fs}$ wavelength-tunable solitons within a wavelength range of $1300–1800\mathrm{nm}$ at a repetition rate of $18\mathrm{MHz}$ . An energy of $2.9\mathrm{nJ}$ per pulse is achieved for a $35\mathrm{fs}$ soliton PCF output centered at $1770\mathrm{nm}$ . Our numerical analysis supports experimental findings and suggests that frequency-shifted solitons in solid-core PCFs can be scaled up to a submegawatt level of peak powers.