Nonlinear optical properties of ferromagnetic insulator Cr2Ge2Te6 and its application for passively Q-switched Er-doped fiber laser

As a member of ferromagnetic insulators (FIs), Cr2Ge2Te6 (CGT) was successfully manufactured as an excellent saturable absorber (SA) for demonstrating passively Q-switched erbium-doped fiber laser (EDFL), for the first time. The saturation intensity and modulation depth of CGT SA was 24.98 MW∕cm2 and 14.10%, respectively. The Q-switched operation was stable over the pump power range of 168.2–529.3 mW and its central wavelength was located at 1530.7 nm. The experimental results suggested that the new 2D material CGT was an effective SA for demonstrating passively Q-switched operation.