基于超小自聚焦（GRIN）光纤探头的干涉条纹对比度，研究了GRIN光纤探头对F-P干涉信号的影响。利用高斯光束分析超小GRIN光纤探头干涉条纹对比度理论公式，建立相应的测试实验系统。实验结果表明：聚焦光斑直径为15 µm的超小GRIN光纤探头，在腔长为600~1350 µm范围内，条纹对比度可以保持在0.8以上。而单模光纤探头的条纹对比度如果要保持在0.8，腔长范围仅为130~530 µm。因此，所研制的超小GIRN光纤探头可有效提高F-P干涉仪在大腔长时的干涉条纹对比度，为超小GRIN光纤探头在较长初始腔长或大动态范围的应用研究中提供了理论依据。

Based on the interference fringe visibility of the ultra-small GRIN fiber probe, we study the influence of the GRIN fiber probe on the F-P interference signal. Furthermore, we analyze a theoretical formula of the fringe visibility of the ultra-small GRIN fiber probe based on the Gaussian beam and establish a corresponding test experimental system for verification. The experimental results show that for the ultra-small GRIN fiber probe with a focal spot diameter of 15 µm, the fringe visibility remains above 0.8 within a cavity length of 600-1350 µm. However, for single-mode fiber probes, the fringe visibility remains at 0.8 within a cavity length range of 130-530 µm. Therefore, the proposed ultra-small GRIN fiber probe improves the fringe visibility of the F-P interferometer for a long cavity length. This paper provides the theoretical foundation for further research into the application of the ultra-small GRIN fiber probe, which requires a long initial cavity length or a large dynamic range.