The scaling potential of beam-splitter-based coherent beam combination

TL;DR

This paper analyzes the power limits of beam-splitter-based coherent beam combination, showing that with current technology, high average powers are achievable, and proposing a path toward megawatt-level scaling.

Contribution

The paper provides a theoretical analysis of power limits in beam-splitter-based coherent beam combination, highlighting the potential for significant power scaling with optimized optics.

Findings

100 kW average power achievable with current optics

High beam quality (M2 ≤ 1.1) maintained at 2% efficiency loss

Potential pathway to megawatt-level power with optimized design

Abstract

The impact of nonlinear refraction and residual absorption on the achievable peak and average power in beam-splitter-based coherent beam combination is analyzed theoretically. While the peak power remains limited only by the aperture size, a fundamental average power limit is given by the thermo-optical and thermo-mechanical properties of the beam splitter material and its coatings. Based on our analysis, 100 kW average power can be obtained with state-of-the-art optics at maintained high beam quality (M2 {\leq} 1.1) and at only 2% loss of combining efficiency. This result indicates that the power-scaling potential of today's beam-splitter-based coherent beam combination is far from being depleted. A potential scaling route to megawatt-level average power is discussed for optimized beam splitter geometry.