The Q-switched pulse and mode-locked pulse were investigated in an all-normal dispersion Yb-doped fiber laser (YDFL) based on the topological insulators (TIs) with mixing of polyvinyl alcohol (PVA) to produce Bi2Se3/PVA film or deposition on the end facet of fiber to manufacture TI-compatible fiber. Through the dark Bi2Se3/PVA films with large nonsaturable loss. the YDFL was operated ... https://mabelandfoxs.shop/product-category/yoto-headphones/