Adaptive modal gain controlling for a high-efficiency cylindrical vector beam fiber laser

Area of Science:

• Laser Physics
• Fiber Optics
• Beam Shaping

Background:

• High-order cylindrical vector beams (CVBs) are crucial for advanced optical applications.
• Controlling transverse modes in fiber lasers remains a significant challenge.

Purpose of the Study:

• To propose and demonstrate a novel method for generating single high-order CVBs with high efficiency and purity.
• To achieve adaptive modal gain control in an ytterbium-doped fiber laser.

Main Methods:

• Utilizing a high-order pump and a specially designed ytterbium-ring doped fiber to tailor modal gain.
• Developing a multimode propagation-rate equation model to analyze transverse mode competition.
• Experimental validation of numerical simulations.

Main Results:

• Achieved a slope efficiency of 79.61% with a low threshold of 47.73 mW.
• Generated high-order CVBs with a modal purity exceeding 95%.
• Demonstrated effective adaptive modal gain control.

Conclusions:

• The proposed strategy enables precise control over modal gain in fiber lasers.
• This method provides a promising route for developing high-power fiber lasers with arbitrary single high-order transverse mode output.