Suppressing nonlinear instability in high-power fiber amplifiers
Abstract
There has been an increasing demand for high-power fiber laser amplifiers for defense applications. The maximal output power achievable for continuous-wave fiber amplifiers is currently limited by the transverse mode instability (TMI). Previous works have pursued single-mode operation as the only route to achieving stable amplification with good beam quality. We propose a paradigm shift from single-mode to highly multimode amplification. A coherent excitation of many fiber modes will efficiently mitigate the thermo-optical coupling and transverse mode instability in a multimode fiber amplifier. Our numerical and theoretical studies show that the TMI threshold power scales linearly with the number of equally excited modes in a fiber. The output beam can be focused to a diffraction-limited spot by shaping the input wavefront. We will conduct comprehensive experimental and theoretical studies on mitigation of nonlinear instabilities in highly multimode fiber amplifiers with killowatt output power. We will demonstrate experimentally a complete control of output beam profile by lossless shaping of input wavefront. The proposed research program focuses on fundamental studies, both experimentally and theoretically, on multi-scale nonlinear light-matter interactions in high-power multimode fiber amplifiers.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 06, 2025
- Source ID
- FA95502410182
Entities
People
- Hui Cao
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- Yale University