1. Sheath: Indoor optical cables generally use polyethylene or flame-retardant polyethylene. The appearance should be smooth, bright, flexible, and easy to peel off.
The outer sheath of poor-quality optical cables has poor finish and is prone to sticking to the tight sleeves and aramid fibers inside.
The PE sheath of outdoor optical cables should be made of high-quality black polyethylene. After the cable is formed, the outer sheath should be smooth, bright, uniform in thickness, and free of small bubbles.
The outer sheath of inferior optical cables is generally produced from recycled materials, which can save a lot of costs. The outer skin of such optical cables is not smooth. Because there are many impurities in the raw materials, the outer sheath of the finished optical cable has many tiny pits. Over time, it will crack and water will enter.
2. Optical fiber: Regular optical cable manufacturers generally use A-grade fiber cores from large manufacturers. Some low-priced and inferior optical cables usually use C-grade, D-grade optical fibers and smuggled optical fibers of unknown origin. It is complex, takes a long time to leave the factory, is often damp and discolored, and single-mode optical fiber is often mixed with multi-mode optical fiber. However, small factories generally lack the necessary testing equipment and cannot judge the quality of optical fiber.
Because such optical fibers cannot be distinguished by the naked eye, common problems encountered during construction are: narrow bandwidth and short transmission distance; uneven thickness and cannot be connected to the pigtail; lack of flexibility of the optical fiber, and the coiling of the fiber. It breaks when it bends.
3. Reinforced steel wires: The steel wires of outdoor optical cables from regular manufacturers are phosphated and have a gray surface. Such steel wires will not increase hydrogen loss, will not rust, and have high strength after being cabled.
Inferior optical cables are generally replaced by thin iron wires or aluminum wires. The identification method is easy. They are white in appearance and can be bent at will when pinched in the hand.
Optical cables produced with such steel wires have large hydrogen losses. Over time, the two ends where the fiber optic boxes are hung will rust and break.
4. Steel armor: Regular production companies use longitudinally wrapped steel strips with anti-rust coating on both sides. Inferior optical cables use ordinary iron sheets, and usually only one side has been treated with anti-rust treatment.
5. Loose tube: The loose tube used to install the optical fiber in the optical cable should be made of PBT material. Such a tube has high strength, does not deform, and is resistant to aging.
Inferior optical cables generally use PVC as casings. The outer diameter of such casings is very thin. They flatten when pinched by hand and break when bent. It is a bit like the straws we use to drink drinks.
6. Fiber paste: The fiber paste in the outdoor optical cable can prevent the oxidation of the optical fiber due to moisture ingress, etc. The fiber paste used in inferior optical fiber will seriously affect the life of the optical fiber.
7. Aramid (winding wire), also known as Kevlar, is a high-strength chemical fiber that is currently used most in the military industry. Military helmets and bulletproof vests are produced from this material.
At present, only DuPont and Aksu of the Netherlands can produce it in the world, and the price is about more than 300,000 per ton.
