▎ 摘　　要

NOVELTY - The saturated absorber has a tapered single-mode fiber and a heterojunction layer coated with a tapered single-mode fiber. The diameter of the tapered single-mode optical fiber is 10-20 mu m, and the thickness of the heterojunction layer is 5-15 mu m. The heterojunction layer includes multiple interleaved graphene layers (104) and bismuth telluride (Bi2Te3) layers (105). The graphene layer is attached to the tapered single-mode optical fiber. The tapered single-mode optical fiber includes a core (101), a cladding (102) and a coating layer (103) sequentially wrapped around the outer layer of the core. The material of the coating layer is acrylic resin, polymethyl methacrylate or polyallyl diethylene glycol carbonate resin. USE - Saturated absorber for fiber laser for laser marking, laser medical treatment, optical communication, and scientific research. ADVANTAGE - The simple structure of saturated absorber ensures high damage threshold and bidirectional transmission fiber laser capable of carrying high power. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for method for preparing a saturated absorber for fiber laser. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic cross-sectional view of saturated absorber. Core (101) Cladding (102) Coating layer (103) Graphene layer (104) Bismuth telluride layer (105)