High power 2 μm picosecond laser delivery in a low loss Nested hollowcore anti-resonant fiber

In this work, we report the fabrication and characterization of a 5-tubes nested hollow-core anti-resonant fiber (Nested HC-ARF), which exhibits outstanding optical performance in terms of a record attenuation value of 0.85 dB/km at 2 μm wavelength and excellent modal. The power handling capability of Nested HC-ARF is also firstly demonstrated in this work. The maximum average power of 60.5 W at 2 μm has been transmitted through the fabricated Nested HC-ARF in robustly single-mode fashion without introducing any damage to the input and output fiber end-faces, which represent the highest average power delivered by HCF in this wavelength, to the best of our knowledge.