Interferometric phase shift compensation technique for high-power, tiled-aperture coherent beam combination.

Area of Science:

• Optics and Photonics
• Laser Physics
• High-Power Laser Systems

Background:

• High-power laser systems often require combining multiple laser beams to achieve desired output power.
• Tiled aperture designs present challenges in maintaining beam coherence and precise phase locking.
• Existing beam combining techniques can be complex, requiring phase retrieval or calibration.

Purpose of the Study:

• To propose and demonstrate a simple, robust coherent beam combining technique.
• To address limitations of current methods in high-power multichannel laser amplifier systems.
• To enable integration into various master oscillator power amplifier (MOPA) architectures.

Main Methods:

• Utilized a photodiode pair for feedback control.
• Employed piezo-actuator mirrors for precise beam steering and phase adjustment.
• Implemented a simple feedback loop for coherent beam combination.

Main Results:

• Demonstrated robust coherent beam combining for two channels.
• Achieved a beam combining bandwidth of approximately 1 KHz.
• Obtained a root-mean-square deviation of approximately λ/25 for phase locking accuracy.

Conclusions:

• The proposed technique offers a simple and effective solution for coherent beam combining.
• The method is scalable and not limited by channel number or single beam power.
• Further enhancements in bandwidth and phase locking accuracy are anticipated, with potential for broad MOPA system integration.