Passively mode-locked fiber lasers dynamic behavior by multimode fiber polarization controller

Passively mode locked fiber lasers (PML-FLs) can produce a variety of phenomena due to the nonlinear effects. With the introduction of the nonlinear polarization rotation (NPR) and a multimode fiber polarization controller (MMF-PC), we observed nonlinear effects in our erbium-doped mode-locked fiber laser, such as the evolution of the soliton bunch to dissipates soliton resonance (DSR) pulses. In the evolution of the soliton bunch to DSR pulses, the soliton square bunch and the multi-longitudinal mode oscillation also appeared in our experiment with the increasing the pump power. To illustrate the importance of MMF-PC, a control experiment is conducted by replacing the MMF-PC with a single mode fiber PC (SMF-PC). The experimental results indicate that the MMFPC are crucial for the evolution of soliton pairs to DSR pulses and the generation of soliton pairs. The NPR modelocked structure is used to achieve dual-wavelength filtering, its strength-dependent non-uniform loss can effectively suppress the mode competition in the gain fibers. The MMF-PC in the mode-locked structure adds a polarization burned hole effect inside the resonator. We achieved dual-wavelength mode locking by adjusting the PC to control the birefringence and loss in the resonator.

Automated summary

Passively mode locked fiber lasers exhibit various nonlinear effects, and in this experiment, we observed the evolution of soliton bunch to dissipates soliton resonance pulses by introducing nonlinear polarization rotation and a multimode fiber polarization controller. The important role of multimode fiber polarization controller in the evolution and generation of soliton pairs was demonstrated.