Broadband anti-bending multimode optical fiber

The invention provides a broadband anti-bending multimode optical fiber. The optical fiber comprises a core layer, a base tube, a sunken cladding layer and an outer cladding layer, wherein cross sections of the base tube, the sunken cladding layer and the outer cladding layer along the radial direction are circular rings, the optical fiber is characterized in that, geO2, p2O5 and F are doped in the core layer, the core layer is a refractive index gradient region, the radius of the core layer is R1, the base tube is arranged on an outer side of the core layer in a sleeving manner, the width ofthe base tube is R2-R1, the sunken cladding layer is arranged on an outer side of the base tube, the width of the sunken cladding layer is R3-R2, the outer cladding layer is arranged on an outer sideof the sunken cladding layer in a sleeving mode, the width of the outer cladding layer is Rmax-R3, and the molar concentration of P2O5 and F in the core layer changes along with the radius of the corelayer. The broadband anti-