Prefabricated optical fiber, optical fiber manufactured by prefabricated optical fiber and capable of filtering high-order mode, and laser

The utility model relates to a prefabricated optical fiber, an optical fiber capable of filtering out a high-order mode and a laser manufactured by the prefabricated optical fiber, the prefabricated optical fiber comprises an optical fiber body, the optical fiber body is provided with a window optical fiber without a coating layer, and the cladding diameter of the window optical fiber is periodically changed. The optical fiber has the beneficial effects that the cladding diameter and the fiber core diameter of the optical fiber manufactured by adopting the prefabricated optical fiber are periodically changed by periodically changing the cladding diameter of the prefabricated optical fiber, non-total reflection is generated from the fiber core to the cladding, and a high-order mode is stripped out of the optical fiber by utilizing the non-total reflection effect, so that the optical fiber of which the high-order mode is filtered is obtained; the defects that a conical microstructure optical fiber high-order mo