Fig. 1. Working principle analysis of single-unit interferometer

Fig. 2. Analysis diagram of interference element

Fig. 3. Function curve of interference element rotation angle - fringe width , and interference fringe and light intensity fitting curve at is 0.02°, 0.05° and 0.10° respectively 干涉元件旋转角度 -条纹宽度 函数曲线，及 分别为0.02°、0.05°及0.10°时的干涉条纹及光强拟合曲线

Fig. 4. Symmetrical oblique fringe images caused by interference element eccentricity error in experiment and simulation

Fig. 5. Schematic diagram of optical fiber digital holographic optical path model and experimental device

Fig. 6. Under different refractive index matching liquid conditions, the ray tracing digital hologram and 3D-reconstruction of refractive index distribution of single-mode fiber and multimode fiber

Fig. 7. Micrograph, interference fringe pattern and refraction index reconstruction of SMF and MMF to be measured