The bending of optical fiber image can be repaired after the fused fiber machine is discharged. According to the inquiry of public information, the pipeline can be repaired and reconnected by optical fiber welding machine because of bending, which is called welding. Radiation loss caused by fiber bending is a complex disadvantage. Although optical fiber is a soft and flexible material, its bending amplitude is greatly limited. Optical fiber can guide light, but it will also change the transmission path of light in bending, from transmission mode to radiation mode, and some light energy will penetrate into the cladding or pass through the cladding to become radiation mode and leak out, resulting in loss. When the bending radius is greater than 5 to 10cm, the loss caused by bending can be ignored.