为解决双包层光纤包层用低折射率涂层在使用过程中机械强度低、体积收缩率高以及耐高温性能差的问题，以十三氟辛醇、甲基丙烯酸异氰基乙酯、聚己内酯三醇合成了氟改性聚己内酯改性剂，以羟基氟化铝纳米颗粒、含氟端巯基超支化丙烯酸酯等为主要原料，合成了超支化聚酯 -氟化铝改性剂。使用红外光谱、凝胶渗透色谱、 X射线衍射等对其结构、分散状态进行了表征。考察了 2种改性剂对低折射率光纤涂层机械强度、体积收缩率、耐高温性的影响。结果表明： 2种改性剂均成功合成，当氟改性聚己内酯质量分数为 30%、超支化聚酯 -氟化铝质量分数为 4%时，涂层力学性能与耐高温性能增强，体积收缩率降低。通过改性提升了双包层光纤在复杂环境下的使用性能。

To address the issues of low mechanical strength，high volumetric shrinkage rate，and poor heat resistance encountered by low refractive index coatings in the cladding ofdouble-clad optical fibers during their use，and to enhance their performance in complex environments， a fluorine-modified polycaprolactone modifier was synthesized using trifluorooctyl alcohol，isophorone diisocyanate，and polycaprolactone triol. Additionally，a hyperbranched polyester-aluminum fluoride modifier was synthesized using hydroxylfluorinated aluminum nanoparticles and fluorine-terminated hyperbranched polyacrylates asmain raw materials. The structure and dispersion state of these modifiers were characterizedusing infrared spectroscopy，gel chromatography，and X-ray diffraction. The effects of the two modifiers on the mechanical strength，volumetric shrinkage rate，and heat resistance of low refractive index fiber coatings were investigated. The results indicated that both types of modifiers were successfully synthesized. The fluorine-modified polycaprolactone at a massfraction of 30% and the hyperbranched polyester-aluminum fluoride at a mass fraction of 4%， when added to the low refractive index coating，effectively enhanced the mechanical properties and heat resistance of the coating，reduced the volumetric shrinkage rate of the coating film， and improved the usage capability of double-clad optical fibers in complex environments.