For the convenience of construction, people will choose indoor optical cables when laying optical cables indoors. Compared with outdoor optical cables, indoor optical cables are relatively soft. Although the construction is convenient, the indoor optical cable has general requirements. Early indoor optical cables used as equipment jumpers and indoor generic cabling usually use tight sleeve optical fibers as the most basic unit, placed in the center, evenly distributed around with aramid fiber, and then loosely wrapped one or more layers of sheathing materials for molding protection. The optical fiber tight sleeve layer is mainly used as a buffer to reduce the lateral bending or impact force of external force on the optical fiber. The tight sleeve layer is usually PVC or LSZH; Aramid fiber is the main tensile element, which firstly bears and offsets the longitudinal tension of the optical cable; The outer sheath is usually made of PVC or LSZH, which can effectively slow down or prevent the force on the optical fiber. The main role is to slow down the impact of environmental temperature changes on the optical fiber. Considering the requirements of indoor installation and wiring, the outer sheath usually has a certain flame resistance and meets the relevant environmental protection requirements