Coherent chirped pulse laser network with Mickelson phase conjugator

Area of Science:

• Optics and Photonics
• Laser Physics
• Nonlinear Optics

Background:

• Coherent coupling of multiple fiber amplifiers is crucial for generating high-power laser beams.
• Nonlinear effects, such as gain saturation, can impact beam quality and phase control in amplifier arrays.
• Chirped pulse compression requires precisely controlled phase and amplitude envelopes for efficient energy delivery.

Purpose of the Study:

• To analyze nonlinear phase-locking mechanisms in large fiber amplifier arrays.
• To identify the optimal configuration for coherently coupling thousands of fiber beams into a single smooth beam.
• To evaluate the performance of Michelson and Mach-Zehnder configurations for phase-locking and beam combination.

Main Methods:

• Theoretical analysis of nonlinear phase-locking dynamics.
• Comparison of Michelson phase-conjugating and Mach-Zehnder configurations for fiber amplifier arrays.
• Investigation of gain saturation effects on pulse envelope and chirp characteristics.

Main Results:

• The Michelson phase-conjugating configuration demonstrates a significant advantage over the Mach-Zehnder setup for coherent coupling.
• Michelson interferometry effectively compensates for phase-piston errors and collimates backward-amplified beams.
• Gain saturation can randomize chirp position within the pulse envelope, reducing interference visibility, particularly for Gaussian envelopes.

Conclusions:

• The Michelson phase-conjugating configuration is highly suitable for coherently coupling large numbers of fiber amplifiers.
• Effective phase error compensation and beam collimation are key benefits of the Michelson approach.
• Pulse envelope shape (sech vs. Gaussian) influences the impact of gain saturation on chirp and interference visibility.