Low-loss single-mode optical fiber applied to long-distance communication transmission

The utility model relates to an optical fiber, in particular to a low-loss single-mode optical fiber applied to long-distance communication transmission. The low-loss single-mode optical fiber comprises a fiber core, a wrapping layer and a coating layer. The fiber core is arranged in the innermost layer of the optical fiber; the wrapping layer is arranged outside the fiber core, made of silicon dioxide and provided with an outer sunken refractive index sectional structure, and a sinking range of the wrapping layer is 0.12%+/-0.04%; and the coating layer is arranged outside the wrapping layer. the coating layer adopts two layers of coating; the inner layer adopts a small modulus coating material for coating and then being cured by ultraviolet?light; and the outer layer adopts an ultraviolet?light coating material for coating and then being cured by ultraviolet?light. Refractive index distribution of a prefabricated rod is adjusted, wire drawing adopts online annealing in step annealing mode, a constant tension programmable logic controller (PLC) automatic control method is adopted in a wire drawing tension control process, small-modulus coating material is adopted in the coating material selecting aspect, microbend loss is reduced, and large plate wire-winding tension in a screening process is controlled to be small.