Mode-Locked Characteristic of L-Band All-Fiber Laser with Different 2D and Quasi-2D Perovskite Saturable Absorbers

In recent years, the quasi-2D perovskite material ((PEA)₂(CsPbBr3)_n-1PbBr₄) has exhibited outstanding optoelectronic performance and environmental stability due to its unique structure, presenting a broad range of potential applications. However, structural differences arising from varying values of "n" result in distinct nonlinear effects in perovskite materials, which have not been thoroughly investigated to date. We conducted a comparative analysis of the mode-locked characteristics of 2D and n = 3, 4, 5, and 6 quasi-2D perovskite materials within an Erbium-doped fiber laser (EDFL). All materials exhibited excellent saturable absorption effects. Besides, the superior performance of the n = 5 quasi-2D perovskite material, with an SNR of 72.59 dB, performed best in terms of the average power and single pulse energy. The five-layer quasi-2D perovskites offer a suitable bandgap, exciton binding energy, and moderate quantum confinement, leading to effective laser operation. Additionally, the optimal nonlinear absorption, refractive index, and thermal stability contribute to stable and high-power laser performance, while suppressing surface states and interface effects. Experimental results indicate that quasi-2D perovskite materials hold significant potential for applications in the realm of ultrafast optics.