Large-energy operation of an Er-doped fiber laser with ZrGeTe4 saturable absorber

ZrGeTe₄ as a layered semiconductor material with good stability and optoelectronic properties, and excellent saturable absorption characteristics, but its application in fiber lasers is still insufficient. In order to explore its application in fiber lasers, we prepared ZrGeTe₄-PVA thin film by liquid phase exfoliation and performed a series of characterizations. A modulation depth of 13.15 %, a non-saturated loss of 6.4 %, and a saturation intensity of 5.5 MW/cm² were obtained. Then used the ZrGeTe₄-PVA thin film as the saturable absorber (SA) in an Er-doped fiber laser (EDFL), the large-energy operation could be realized. In the case of a cavity length of 234 m, when the pump power was increased to 1229 mW, a maximum single pulse energy of about 32.72 nJ was achieved, with a repetition frequency of 859 kHz. To the best of our knowledge, this is the highest single-pulse energy achieved in an EDFL based on ZrGeTe₄-SA. This experiment shows that the ZrGeTe₄ is a promising two-dimensional (2D) material with good nonlinear absorption properties, proving that it is a promising pulse modulation of SA and laying a foundation for its subsequent study in fiber lasers.