Decoupled tip-tilt detection and steering of beamlets in a fiber laser array using sequential tagging lasers

Area of Science:

• Optics and Photonics
• Laser Technology
• Adaptive Optics

Background:

• Tiled fiber laser arrays offer power scaling and atmospheric turbulence mitigation.
• Precise tip-tilt control of individual beamlets is essential for far-field overlap and high beam quality.
• Far-field coupling of beamlets poses a challenge for individual identification and control.

Purpose of the Study:

• To develop a novel method for decoupled tip-tilt detection and steering of beamlets in tiled fiber laser arrays.
• To overcome the challenge of beamlet coupling in the far-field.
• To enable direct and individual control of beamlet pointing.

Main Methods:

• A pulsed tagging laser is introduced into each beamlet with unique pulse sequences.
• Synchronization of tagging laser pulses and camera exposure allows detection of single spots per image.
• The detected spot location directly corresponds to its beamlet, enabling individual identification.

Main Results:

• Demonstrated direct and decoupled tip-tilt detection of individual beamlets in the far-field.
• Successfully steered individual beamlets using the proposed method.
• Validated the efficiency of the approach with a seven-beamlet adaptive fiber collimator array.

Conclusions:

• The proposed method effectively decouples beamlets for direct tip-tilt detection and steering.
• This technique is crucial for achieving high beam quality in tiled fiber laser arrays.
• Represents the first demonstration of direct, decoupled far-field beamlet control in such arrays.