kiudlaserid

Kiudlaserid, or fiber lasers, are a class of lasers in which the gain medium is an optical fiber doped with rare-earth ions such as ytterbium, erbium, or thulium. The combination of light confinement and amplification in a single fiber yields high beam quality and compact hardware compared with many other laser types.

A typical kiudlaser comprises a doped fiber, pump diodes, and a laser cavity formed by fiber Bragg gratings or end mirrors. Pump light excites the dopant ions and stimulated emission propagates along the fiber. The guiding structure provides efficient cooling and enables power scaling by using longer fibers or multiple fiber channels, sometimes combined coherently.

Common variants include Yb-doped fiber lasers (approximately 1.0–1.1 μm), Er-doped fiber lasers (~1.55 μm, telecom-friendly), and Tm-doped fiber lasers (~2 μm). They are widely used in material processing (cutting, welding, drilling), micromachining, coating applications, telecommunications, and sensing. Medical uses exist but require careful control of wavelength, stability, and safety.

Advantages include high wall-plug efficiency, compactness, robust alignment-free beam delivery via flexible fibers, and very good beam quality, especially in single-mode forms. Limitations encompass nonlinear effects at high powers (e.g., self-phase modulation, Raman scattering), risk of fiber fuse, splicing and handling challenges, and the cost of high-power diodes and specialty fibers.

Current research focuses on further power scaling, coherent beam combining, and expanding wavelength reach through new dopants and nonlinear conversion, to broaden applications in industry, science, and medicine.