锥形光纤是指在普通的柱形光纤上采用熔融拉锥、机械抛磨、化学腐蚀等手段形成的纤芯半径随长度变化的一种光纤，纤芯半径变化的部分被称为锥区。一段双包层光纤整段都为锥区时被称之为长拉锥双包层光纤(T-DCF，简称锥形光纤)。总结了锥形光纤的发展，简述了锥形光纤在光纤激光领域的应用优势以及基本理论，并对长拉锥双包层光纤在光纤激光应用的发展趋势做了探讨。

Tapered fiber is fabricated from traditional uniformed fiber using fused conical tapering, mechanical affection, chemical corrosion and so on, whose radius is various with the length of fiber. The changing part of fiber core is called tapered area. When the tapered area is distributed in whole double-clad fiber, the fiber is called a tapered double-clad fiber (T-DCF). The developing progress of tapered fiber is summarized, the advantages and basic theories of application of T-DCF in fiber laser area are described, some major experimental results of T-DCF are discussed, and the developing trend of T-DCF in fiber laser application is listed.