Generation of dark-bright-bright solitons in Er-doped fiber laser based on ferromagnetic insulator Cr2Ge2Te6

In our work, the ferromagnetic insulator (FI) Cr2Ge2Te6 was utilized as a saturable absorber (SA) successfully to demonstrate Er-doped fiber laser. Its modulation depth is 6.24%, and saturable intensity is 7.58 MW/cm2. Based on the SA which was prepared by mixing CGT with polyvinyl alcohol (PVA), stable dark-bright-bright solitons with a threshold power of 110 mW at the fundamental frequency of 5.64 MHz were acquired for the first time. Our results suggest that CGT is an efficient SA candidate for demonstrating dark-bright-bright soliton fiber lasers because of excellent nonlinear optical characteristics.