Fig. 1. Experimental scheme for high-power broadband SC generation. ISO, isolator; LD, laser diode; Amp, amplifier.

Fig. 2. (a) Spectrum and (b) power evolution of the pump laser with increasing LD power.

Fig. 3. Measured spectral evolution of the SC with increasing pump laser power at 10 m GRIN MMF. The legend represents the SC output power versus the pump laser output power.

Fig. 4. (a) The final spectrum of the SC at 10 m GRIN MMF with an average SC output power of 40.6 W. The inset shows the near-field beam profiles of the total and filtered SC at different central wavelengths of 730 nm, 620 nm, 532 nm, and 470 nm measured at maximum SC output power. (b) The SC output power versus the pump laser output power.

Fig. 5. The experimental scheme for the hundred-watt level SC generation from a GRIN MMF. ISO, isolator; LD, laser diode; Amp, amplifier; MFA, mode field adapter.

Fig. 6. The dependence of the SC output characteristics on the pulse duration of the seed laser. (a) The SC output power and (b) the SC output spectra.

Fig. 7. The final spectrum of the SC at 10 m GRIN MMF with an average output power of 204 W. The repetition rate and pulse duration of the seed laser are fixed at 2 MHz and 3 ns, respectively. The inset shows the near-field beam profiles of the total and filtered SC at different central wavelengths of 730 nm and 620 nm measured at maximum SC output power.

Fig. 8. The group velocity matching curves of the first three radially symmetric modes.

Fig. 9. The spectral evolution of the SC with increasing GRIN MMF lengths under different pump laser powers of (a) 17.5 W, (b) 27.9 W, (c) 37.9 W, and (d) 70.1 W. The red dotted lines represent the cut-off wavelength of the DWs, i.e., 600 nm. Region i is the spectral region dominated by the GPI effect, and region ii is the spectral region dominated by both the DW and the GPI effect. The wavelength peaks in the short wavelength region that appeared in (a)–(d) basically all correspond to the position of GPI peak.

Fig. 10. The spectral evolution of the SC with two kinds of GRIN MMF lengths under different pump laser powers of (a) 37.9 W and (b) 70.1 W. The inset is a zoomed-in view.