实验发现飞秒激光单步刻蚀的光纤微腔两个反射壁与纤芯轴向并不完全垂直，微腔形状与飞秒激光经显微物镜聚焦后的焦点相对于光纤的位置有关。当激光经显微物镜聚焦于光纤侧表面时，刻蚀的微腔形状近似V型。与常规的光纤法布里珀罗(F-P)腔相比，V型光纤微腔干涉谱出现了自由光谱范围、微腔光损耗以及干涉条纹对比度与波长有关等反常现象。通过引入倾斜因子概念，构建了V型光纤微腔模型，推导出V型F-P腔干涉公式，初步建立了V型光纤微腔干涉理论。利用该理论研究了V型光纤微腔的干涉谱特性，数值模拟了不同倾斜度对光纤微腔干涉谱的影响。理论分析结果与实验光谱测量结果相符。

It is found that two reflected walls of fiber micro-cavity fabricated by one-step femtosecond laser micro-machining technology are not perpendicular to the fiber axis. The cavity shape is decided by the relative position of focused femtosecond laser and fiber, which can be approximated as V-shaped when femtosecond laser is focused on the side surface of the fiber. Compared with conventional fiber Fabry-Pérot (F-P) cavity, the free spectral range, optical loss and the interference fringe of the V-shaped fiber F-P cavity contrast change with the wavelength, showing abnormal characteristics. By introducing the concept of inclination factor, V-shaped fiber micro-cavity model is constructed, the cavity interference formula and the V-shaped micro-cavity interference theory are established. According to this theory, the effect of reflector inclination degree on interferogram characteristics of V-shaped F-P micro-cavity is simulated. The simulated interferogram is verified by experimental results.