Novel Bidirectional Output Ytterbium-Doped High Power Fiber Lasers: From Continuous to Quasi-Continuous

Area of Science:

• Laser Physics and Photonics
• High-Power Fiber Lasers
• Materials Science

Background:

• Traditional ytterbium-doped fiber lasers predominantly utilize a unidirectional output structure.
• Existing unidirectional output fiber lasers (UOFLs) face limitations in cost-effectiveness and efficiency for high-power applications.
• There is a need for advanced fiber laser architectures to meet growing industrial demands.

Purpose of the Study:

• To propose and theoretically model a novel bidirectional output fiber laser (BOFL) architecture.
• To investigate the advantages of BOFLs over traditional UOFLs, particularly concerning nonlinear effects.
• To experimentally demonstrate high-power continuous wave (CW) and quasi-continuous wave (QCW) BOFLs.

Main Methods:

• Theoretical modeling and simulation of the BOFL, including analysis of nonlinear effects.
• Experimental implementation of CW BOFLs, including integration with oscillating amplifying structures.
• Experimental implementation of QCW BOFLs using pump source modulation techniques.

Main Results:

• Demonstrated a near-single-mode bidirectional 2 × 4 kW CW output (total > 8 kW) using an integrated structure.
• Achieved a CW bidirectional 2 × 5 kW output (total > 10 kW) with a simple BOFL configuration.
• Realized a near-single-mode QCW laser with a peak output of 2 × 4.5 kW (total peak power > 9 kW).

Conclusions:

• The developed BOFL architecture offers significant advantages in terms of cost reduction and efficiency improvement.
• Both CW and QCW BOFLs demonstrate record-high power outputs, surpassing previously reported levels.
• The BOFL technology shows substantial potential for widespread industrial applications requiring high-power laser sources.