Compared with traditional uniform fiber, the long tapered fiber has the advantage of suppressing nonlinear effects and maintaining excellent beam quality. Both the cladding size and core size of the long tapered fiber reported so far vary simultaneously in a constant core-to-cladding diameter ratio (CCDR) along the length. In this work, we propose a technique for preparing cladding uniform core tapered fiber (CUCTF) with a varying CCDR, and have successfully fabricated CUCTF. The core diameters of narrow end and wide end are 31.2 μm and 52.5 μm, respectively. The cladding diameter is always 400 μm along the length. The laser performance of CUCTFs with different structures (wide to narrow, narrow to wide) are investigated based on a co-pumped fiber amplifier. Between them, the CUCTF with the wide to narrow structure has a better M² factor of 1.455 due to mode filtering.

与传统的均匀光纤相比，长锥形光纤具有抑制非线性效应并保持优异光束质量的优势。到目前为止，报道的长锥形光纤的包层尺寸和纤芯尺寸都沿长度方向以恒定的纤芯与包层直径比（CCDR）同时变化。在这项工作中，我们提出了一种制备具有变化的CCDR的包层均匀纤芯锥形光纤（CUCTF）的技术，并成功地制造了CUCTF。窄端和宽端的芯直径分别为31.2μm和52.5μm。包层直径沿长度始终为400μm。基于共泵浦光纤放大器，研究了具有不同结构（宽到窄，窄到宽）的CUCTF的激光性能。在它们之间，具有从宽到窄结构的CUCTF具有更好的M由于模式滤波，1.4的²倍。