Thulium fiber lasers, operating at a wavelength of 2 micrometers, are valued for applications in medicine, materials processing, and defense. Their longer wavelength makes stray light less damaging compared to the more common ytterbium lasers at 1 micrometer. Yet, despite this advantage, thulium lasers have been stuck at around 1 kilowatt of output power for more than a decade, limited by nonlinear effects and heat buildup. One promising route to break this barrier is inband pumping—switching from diode pumping at 793 nm to laser pumping at 1.9 µm. This approach improves efficiency and reduces heat, but it introduces new challenges for fiber components, especially the cladding light stripper (CLS).

In the world of optics, tiny structures called microcavities—often no wider than a human hair—play a crucial role in technologies ranging from lasers to sensors. These microscopic resonators trap light, allowing it to circulate millions of times within their boundaries. When perfectly shaped, light inside them moves in smooth, circular paths. But when their symmetry is slightly disturbed, the light begins to behave unpredictably, following chaotic routes that can lead to surprising effects like one-way laser emission or stronger light–matter interactions.

Many modern artificial intelligence (AI) applications, such as surgical robotics and real-time financial trading, depend on the ability to quickly extract key features from streams of raw data. This process is currently bottlenecked by traditional digital processors. The physical limits of conventional electronics prevent the reduction in latency and the gains in throughput required in emerging data-intensive services.