Tapered fiber is a potential candidate for delivering high-energy, ultrafast lasers with high beam quality

https://phys.org/news/2023-11-tapered-fiber-potential-candidate-high-energy.html

"flexible/ compact, high conversion efficiency,... unwanted nonlinear effects threshold proportional to mode field diameter, and longitudinally increased core/cladding diameter of tapered fiber balances nonlinear effects and beam quality... combines tapered confined-doped fiber and high-order dispersion compensation technique... high-energy/ high peak power monolithic CPA system with near diffraction-limited beam quality (M2=1.20)... advanced manufacturing, photomedicine, and ultrafast physics"