Here, we demonstrate the six-wavelength mode-locking and hybrid mode-locking operation in an erbium-doped fiber laser (EDFL) with an ultra-long-period grating (ULPG) by properly adjusting the pump power and the cavity parameters. The ULPG is fabricated by using the fused biconical method with a GPX-3000 glass processing system. Study found that, the ULPG exhibits dual-function, that is, mode-locker and multiwavelength filter. Our finding implies that apart from its fantastic sensing application, the ULPG may also possess attractive nonlinear optical property for ultrafast photonics.
We experimentally demonstrated a tunable triple-wavelength mode-locked erbium-doped fiber laser with few-layer topological insulator: Bi2Se3/polyvinyl alcohol solution. By properly adjusting the pump power and the polarization state, the single-, dual-, and triple-wavelength mode-locking operation could be stably initiated with a wavelength-tunable range (∼1 nm) and a variable wavelength spacing (1.7 or 2 nm). Meanwhile, it exhibits the maximum output power of 10 mW and pulse energy of 1.12 nJ at the pump power of 175 mW. The simple, low-cost triple-wavelength mode-locked fiber laser might be applied in various potential fields, such as optical communication, biomedical research, and sensing system.