Why to discover indoor 4 core fiber optic cable construction to be able to be like after finishing fiber core twisted-pair is same winding fold?

Because in the construction process, the cable sheath is pulled when threading, and the tension is too large. When the construction is completed, the sheath will naturally shrink, which will be associated with the fiber core. Finally, under the action of sheath, fiber core will be twisted, the fundamental reason is due to the construction method error caused, but also affect the transmission performance of optical cable.