Novel adaptive fiber-optics collimator for coherent beam combination

Area of Science:

• Optics and Photonics
• Laser Physics
• Optical Engineering

Background:

• Fiber laser beam combining systems face challenges with end-cap/tilt aberrations.
• Accurate aberration compensation is crucial for high-power coherent beam combination (CBC).

Purpose of the Study:

• To experimentally validate a novel adaptive fiber-optics collimator (AFOC) design.
• To assess the AFOC's capability in compensating for end-cap/tilt aberrations in fiber laser systems.
• To demonstrate the AFOC's effectiveness in high-power CBC.

Main Methods:

• Fabrication of a new AFOC utilizing flexible hinges and levers to enhance the fiber end cap's movable range.
• Comprehensive performance testing of the AFOC, including control range, frequency response, and control accuracy.
• Implementation of coherent beam combination (CBC) of two fiber amplifiers with simultaneous end-cap/tilt and phase-locking control.

Main Results:

• The novel AFOC successfully compensated for end-cap/tilt aberrations during CBC.
• Average normalized power in the bucket (PIB) increased from 0.311 to 0.934 with active compensation.
• Fringe contrast improved to over 82% from 0% when both tilt and phasing controls were active.

Conclusions:

• The developed AFOC provides a promising structure for effective tilt aberration control in high-power CBC systems.
• The AFOC's design enables simultaneous compensation for multiple aberrations, enhancing system performance.
• Experimental validation confirms the AFOC's significant contribution to improving laser beam quality and combining efficiency.