目的 通过对硫醇烯烃官能化聚硅氧烷光固化体系中光引发剂的筛选，用于制备低折射率、低损耗的大芯径光纤涂层。方法 采用乙烯基硅油、巯基硅油和光引发剂，配制出硫醇烯烃官能化聚硅氧烷光固化体系，并研究其对光纤内涂层折射率、凝胶含量、固化时间、固化状态的影响。将最佳比例的引发剂进行了现场应用试验，并测试光纤损耗。结果 在五种单组分光引发剂中，BP光引发制得的涂层的折射率为1.5795，最佳加入质量分数为0.2%，光纤损耗为7.1 dB/km。单组分Irgacure184光引发制得的涂层的固化时间短，达到20 s深层固化，折射率为1.5858，最佳加入量为1%，光纤损耗为8.3 dB/km。在4种复配体系中，Irgacure1173+BP的引发效果好，固化时间20 s，折射率1.5842，1173:BP最佳质量分数之比为2∶1，光纤损耗最低，为6.7 dB/km。结论 在硫醇烯烃官能化聚硅氧烷光固化体系中，加入光引发剂BP可有效降低折射率，Irgacure184制得的涂层的固化时间短，1173和BP复配所制得的涂层具有最低的光纤损耗。

The work aims to prepare low-refractive index and low-loss large-core diameter optical fiber coating by performing screening test of photoinitiator. Thiol polydimethylsiloxane, vinyl silicone and photoinitiators were used to prepare polysiloxane UV-curing system functionalized by thiol-olefin. The effects of the system on refractive index, gel content, curing time and curing state were investigated. Then optimal photoinitiator was applied to field application test and fiber loss testing. In the five single-component photoinitiators, for coatings prepared by BP photoinitiation, the refractive index was 1.5795, optimal content 0.2% and fiber loss 7.1 dB/km; for coatings prepared by single-component Irgacure 184, the curing duration was 20 s, refractive index 1.5858, optimal content 1% and fiber loss 8.3 dB/km. In the four combined system, for coatings prepared by Irgacure1173+BP, the curing duration was 20 s, refractive index 1.5842, 1173: BP=2:1 and fiber loss 6.7 dB/km (the minimum). The addition of photoinitiator BP can reduce refractive index effectively in the polysiloxane UV-curing system functionalized by thiol-olefin. Coatings prepared by irgacure 184 are cured rapidly while coatings prepared by Irgacure1173+BP perform exhibits the lowest fiber loss.