Complex variable-diameter optical fiber and preparation method and application thereof

The invention relates to the technical field of optical fiber preparation, and particularly discloses a complex variable-diameter optical fiber and a preparation method and application thereof. According to the method, after corrosion and heat treatment are carried out on the specific position of the optical fiber preform, expanding and tapering of the optical fiber are achieved by means of axial force, a plurality of non-equal-diameter areas are formed, and preparation of the complex variable-diameter optical fiber is successfully achieved by combining annealing and wire drawing processes. The preparation method of the complex variable-diameter optical fiber is simple and convenient, the preparation yield of the complex variable-diameter optical fiber is greatly improved, and the problems that in the prior art, in the preparation process of the complex variable-diameter optical fiber, wire drawing conditions of a wire drawing tower need to be modified, operation is complex, and the yield of the prepared comp