Dark–bright solitons within an erbium-doped fiber laser based on Cr ₂ Ge ₂ Te ₆ saturable absorber

In recent years, two-dimensional (2D) materials have been proven to be saturable absorbers (SAs) in fiber lasers to generate ultrashort pulsed lasers. Thus, exploration of a new type of 2D materials has great significance in promoting the development of the ultrashort fiber laser field. As a new type of ferromagnetic insulator, <i>C</i><i>r</i>₂<i>G</i><i>e</i>₂<i>T</i><i>e</i>₆ (CGT) is expected to possess excellent nonlinear absorption properties, which can be used as a broadband optical modulator of ultrafast pulsed lasers. However, there is still a lot of room to explore the optical properties of CGT. In this investigation, we prepared the CGT SA with a modulation depth of 1.26% and a saturation intensity of 10<i>M</i><i>W</i>/<i>c</i><i>m</i>² and studied its morphological and optical properties. As far as we know, the stable dark-bright soliton was generated by an erbium-doped fiber laser based on CGT SA for the first time. That indicates the CGT SA has great potential for investigating the mechanism of dark-bright solitons.