Identify the good and bad of fiber optic cable

Update:30 Mar 2018

1, the outer skin: indoor fiber optic cable generally u […]

1, the outer skin: indoor fiber optic cable generally use polyvinyl chloride or flame retardant PVC, the appearance should be smooth, bright, flexible, easy to peel. Poor quality optical cable has a poor finish and is easily adhered to the inner sleeve and aramid.

The PE sheath of the outdoor cable should be made of high-quality black polyethylene. After the cable is cabled, the jacket is smooth, bright, uniform in thickness, and free of small air bubbles. The jacket of poor quality optical cable is generally produced from recycled materials, which can save a lot of costs. The surface of the optical cable is not smooth. Because there are many impurities in the raw materials, there are many tiny pits on the outer surface of the cable. Wow it takes a long time to crack. water.

2, the optical fiber: regular cable manufacturers generally use the A-grade core of Dachang, some low-cost inferior fiber optic cable usually use C-class, D-class optical fiber and unsolicited smuggling optical fiber, these fibers due to complex sources, the factory time is longer, Frequently, the color has changed and the single-mode optical fiber is often mixed in the multi-mode optical fiber. However, the general small-scale plant lacks the necessary detection equipment and cannot judge the quality of the optical fiber. Due to the inability of the naked eye to distinguish such optical fibers, the problems encountered during construction are: narrow bandwidth, short transmission distance, uneven thickness, and inability to dock with pigtails; the optical fiber lacks flexibility, and when a fiber is bent, it is broken.

3, strengthen the steel wire: The wire rope of the outdoor cable of the regular manufacturer is phosphatized and the surface is gray. Such steel wire does not increase hydrogen loss, rust, and high strength after being cabled. Inferior optical cables are generally replaced with thin wires or aluminum wires. The method of identification is very easy - the appearance is white, and it can be bent freely in the hand. Optical cables produced with such steel wires have large hydrogen losses and take a long time, and the two ends of the hanging optical fiber box will rust and break.

4, the steel file: regular production companies use double-sided brush anti-rust coating longitudinal banding strip, poor quality fiber optic cable using ordinary iron, usually only one side for anti-rust treatment.

5. Loose Tube: The loose tube used to hold the fiber in the fiber optic cable should be made of PBT material. This type of tube has high strength, no deformation, and no aging. Poor optical cable is generally made of PVC as a sleeve. The outer diameter of the sleeve is very thin, and it is flattened by hand. It is a bit like the straw we drink.

6. Ointment: Ointments mainly consist of fiber cream and cable cream. Under normal circumstances, the fiber cream should be filled with the entire loose tube, and the cable paste should be filled with every gap of the cable core under pressure. There is a half-full or less filling of the fiber paste. Some of the cable paste is only applied one layer outside the cable core, while others are not filled in the middle of the cable. In this way, the optical fiber will not be well protected, affecting the transmission performance such as attenuation of the optical fiber, and the poor waterproof performance will not reach the national standard. Once the optical cable accidentally seeps, it will lead to water leakage of the entire link. Under normal circumstances, even if accidental seepage occurs, it is only necessary to repair the water seepage section and it is not necessary to revisit it. (The national standard requires that the water blocking performance be: three meters of fiber optic cable, one meter of water column pressure, 24 hours without seepage.) If you use poor grease the same problem will occur, and may be due to the thixotropy of the ointment It will cause the micro-bending loss of the optical fiber, and the transmission performance of the entire link will be unacceptable. If the grease is acidic, it will react with the metal material in the cable to precipitate H molecules, and the hydrogen molecules will rapidly increase when the optical fiber meets H, resulting in the entire Link interruption transmission.

7,Kevlar: Kevlar, also known as Kevlar, is a high-strength chemical fiber that is currently used most in military industry. Military helmets and bullet-proof vests are the materials of this kind. By 2013, only DuPont and Aksu in the Netherlands could produce, and the price was about 300,000 tons. Indoor fiber optic cables and power overhead aerial cables (ADSS) are all reinforced with aramid yarns. Due to the high cost of aramid fibers, poor quality indoor fiber optic cables generally have a very small outer diameter, which can reduce the cost of several aramid fibers. Such a cable is easily broken when it is worn. Because ADSS fiber optic cable is based on the span, the wind speed per second to determine the use of aramid fiber cable, generally do not dare to cut corners.

8, water blocking zone: The water-absorbing resin or water-blocking yarn used in optical fiber cable has a strong water absorption performance through the uniform distribution of high water-absorbing resin inside the product. Under the joint action of soaking pressure, affinity and rubber elasticity, Superabsorbent resin can quickly inhale water several times its own weight. In addition, the water-blocking powder will instantly swell the gel upon contact with water, and the water will not be squeezed out no matter how much pressure is applied thereto. Therefore, the cable core is covered with a water-absorbing resin-containing water blocking tape, and in the event that the outer wall of the cable is damaged, the superabsorbent resin in the wound portion is sealed due to its expansion and water entry can be minimized. Poor quality optical cables usually use non-woven fabrics or paper tapes. Once the cable is damaged, the consequences will be very serious.