Fig. 1. The coordinate diagram of phase shift

Fig. 2. The coordinate diagram of optical fiber when measuring the internal stress

Fig. 3. The framework diagram of multi-core fiber comprehensive parameter test system

Fig. 4. The device diagram of multi-core fiber comprehensive parameter test system

Fig. 5. The reconstruction diagram of the refractive index profile of the seven-core fiber

Fig. 6. The reconstruction diagram of the seven-core fiber geometry

Fig. 7. The reconstruction diagram of the stress distribution in single-mode fiber