MXene Ti₃C₂T_x Modulator for Robust Generation of Soliton Molecules

Abstract In recent years, two‐dimensional materials have been widely used in the field of optics due to their unique nonlinear optical properties, broadband saturation absorption and ultrafast recovery time. MXene Ti₃C₂T_x is a kind of emerging two‐dimensional materials with large modulation depth, high damage threshold, and excellent electrical conductivity with near zero bandgap structure. However, MXene has seldom been applied in ultrafast photonics, especially the generation of ultrastable soliton molecules. In this paper, MXene is prepared and applied in the erbium‐doped fiber laser. The nonlinear optical properties of MXene Ti₃C₂T_x are studied experimentally. The center wavelength, 3‐dB bandwidth, fundamental frequency and the pulse duration of the conventional soliton are 1566.1 nm, 1.21 nm, 6.09 MHz and 993 fs, respectively. By adjusting the polarization state and pump power, the soliton molecules can be obtained in the laser cavity. Especially, two kinds of soliton molecules with CW peak and without CW peak are observed, respectively. Experimental results show that MXene saturable absorber (SA) can bear a high pump power. This work demonstrates that MXene Ti₃C₂T_x can be used as an excellent SA. Hence, we believe that this kind of optical material has many applications such as optical communication, optical logic gates and nonlinear devices, etc.