High-power fiber lasers are a key technology behind many tools we use today, from precision metal cutting and medical procedures to advanced sensing and communications. They are valued for producing extremely bright, high-quality light while staying compact, efficient, and reliable.

For everyday applications, fiber lasers often operate in multimode, meaning the light spreads across multiple patterns. But more advanced uses—such as combining many laser beams into a single, extremely powerful beam—require much stricter control. These systems depend on single-mode lasers with very stable wavelengths, which produce a clean, focused beam that can travel long distances or be combined with other lasers efficiently.

As fiber lasers reach higher power levels, especially at wavelengths near 1 µm and 2 µm, new challenges appear. Heat buildup and nonlinear effects inside the fiber can distort the beam or limit how much power the system can safely handle. Overcoming these limits is essential for developing next-generation laser systems.

At the Laser Plasma Laboratory (LPL), our research focuses on pushing fiber lasers beyond these boundaries. We study ytterbium-doped (Yb) fiber lasers around 1 µm and thulium-doped (Tm) fiber lasers near 2 µm, exploring new designs and operating regimes that allow higher power without sacrificing beam quality. This includes scaling Yb fiber amplifiers to multi-kilowatt levels and investigating more efficient approaches—such as in-band pumping—for Tm fiber lasers to reduce heat and improve performance.

By combining computer modeling with hands-on experiments, our work helps guide the design of more powerful, efficient, and stable fiber lasers that can support future scientific research and real-world technologies.