The loss is mainly caused by the scattering and escape of light generated by the fiber during bending.When the light is transmitted in a curved fiber, part of the light will escape from the fiber due to the changing propagation speed and direction of the light in the medium, thus causing the loss of the optical signal.In addition, the propagation of light in the optical fiber is through full reflection, and at the bend, the degree of incidence angle of light may exceed the critical angle of full reflection, resulting in scattering phenomenon, which will also cause the loss of optical signal.The size of the macrobending loss is affected by many factors, including the bending radius, the type and material of the fiber, and the outer coating of the fiber. A smaller bending radius will increase the scattering and escape of light, resulting in increased macrobending loss.The special outer coating can reduce the scattering and escape of light, thus reducing the macrobending loss.