Development status of high power fiber lasers and their coherent beam combination

Abstract

High-power fiber laser has been emerged great potential in a wide range of applications and becomes a robust candidate for high energy solid state laser system. To further increase the output brightness of single-channel fiber laser, high-brightness pump sources and high-power-handling passive components should be fabricated and utilized in the fiber laser systems, in addition to the advanced techniques for multiple nonlinear effects managements. The state-of-the-art high power fiber lasers are reviewed, in terms of narrow-linewidth fiber lasers, broadband fiber lasers and fiber lasers at 2 µm. Coherent beam combining is a promising technique to obtain higher output power while maintaining excellent beam quality simultaneously, which breaks through the bottlenecks of single-channel fiber laser. Based on a series of key techniques for coherent beam combining, high-power coherent beam combining of fiber lasers could be enabled with high combining efficiency. In this paper, we review the progress of high-power fiber lasers and their coherent beam combining in the recent decade, particularly the relevant work in our group. The future prospects of fiber lasers and coherent beam combining technique are also discussed.

Sidelobe suppression for coherent beam combining with laser beams placed along a Fermat spiral

“…Because of the influence of heat damage, nonlinear effect, mode instability, and brightness of the pump source, the output power of a single laser is limited [1][2][3] . Coherent beam combining (CBC) of multiple laser modules is an effective solution to obtain higher output power and good beam quality simultaneously [4,5] . When the optical phase and optical axes of each laser beam are controlled, the whole laser array can be regarded as a single laser with a large aperture [6][7][8] .…”

Experimental Demonstration of Central-Lobe Energy Enhancement Based on Amplitude Modulation of Beamlets in 19 Elements Fiber Laser Phased Array

“…Coherent beam combination (CBC) of fiber laser phased array (FLPA) provides an approach for achieving laser output with high energy density and high beam quality [1][2][3][4][5]. A nearly diffractionlimited equivalent large-aperture output laser can be obtained by correcting the phase and tip/tilt errors in each sub-aperture of the FLPA.…”

Greater than 2 kW all-passive fiber Raman amplifier with good beam quality

“…Remarkable progress has further promoted diverse applications in the fields of manufacturing industry, medical science, remote sensing and communications. At the time of writing, the most common implementation is based on active fibers such as Yb-doped fiber, boosting the record for power scaling to greater than 10 kW [3][4][5] . Another way to obtain high-power laser output is the Raman fiber laser (RFL), which employs the stimulated Raman scattering (SRS) effect in a piece of passive fiber without any rare-earth dopants [6][7][8] .…”