How To Distinguish The Quality Of Optical Fiber Cable
1. Look at the grease. The grease mainly includes fiber paste and cable paste. The fiber paste should fill all loose tubes under the normal condition of the reel, and the cable paste should fill every gap of the optical cable core under pressure. Nowadays, there are ways to fill the fiber paste half full or less. For the cable paste, some just apply a layer on the outside of the cable core, and some are not filled between the two ends of the optical cable. This will make the optical fiber not well maintained, affect the transmission performance such as optical fiber attenuation, and the waterproof function is not up to the national standard. Once the optical cable accidentally sees water, it will cause the entire link to seep water and become invalid. Under normal conditions, even if accidental water seepage, you only need to repair the part of the water seepage and you don't need to do it again. If you use poor grease, the above questions will appear, and the thixotropy of the grease may be poor, which will cause microbending loss of the optical fiber, and the transmission characteristics of all links are unqualified; if the grease is acidic, it will Metal materials react with H evolution to precipitate hydrogen molecules, and the attenuation of the optical fiber will rapidly increase when it encounters H, causing all links to stop transmission.
2. Sheath, optical cable sheath not only has to get used to many different and messy climatic environments, but also to ensure long-term (at least 25 years) stability. The spool optical cable sheath must not only have a certain strength, but also have low thermal deformation, abrasion, water permeability, thermal shrinkage and friction coefficient, but also have the characteristics of strong resistance to environmental stress and good data processing functions. Although the sheath material that is rarely used or poorly used can pass the factory inspection, it will show cracks and water seepage after a period of use due to its quality defects. It is even more severe if recycled plastic is used to replace the high-quality polyethylene sheath material. The fiber optic cable made of high-quality sheath material has a flat, bright, uniform thickness and no air bubbles, otherwise it will appear as a rough surface of the fiber optic cable, and because there are many impurities in the material, you can find that the fiber optic cable skin has a lot of very fine Potholes, and because of the thin thickness, the overall outer diameter of the optical cable will be much smaller than that of a high-quality optical cable. Indoor optical cables are usually made of high-quality flame-retardant polyvinyl chloride. The exterior should be lubricated, bright, flexible, and easy to peel; otherwise, it will show the appearance of poor skin finish, simple and tight-fitting fiber and aramid adhesion.
3. Steel strips and aluminum strips. The steel strips and aluminum strips in the optical cable are mainly used to protect the optical fiber from mechanical side pressure and moisture resistance. Better optical cables usually use chrome-plated steel strips. The inferior fiber optic cable replaces the chrome-plated steel strip with the usual iron sheet or black sheet (uncoated steel strip) that has been treated with rust prevention on one side. After a long time, the fiber optic cable will appear rusty and the hydrogen loss of the fiber will increase. Because it is easy to separate from the sheath and cannot form a bonded protective layer, the moisture barrier function is also very poor; some use tin-plated steel strips instead of chrome-plated steel strips. The appearance of tin-plated steel strips and bubbles are inevitable coils. Therefore, corrosion occurs easily under humid atmosphere and surface condensation or immersion conditions, especially under acidic conditions. The tin-plated layer has poor heat resistance, and the melting point is only 232 degrees Celsius. During use, the high temperature during the extrusion of the sheath makes the peeling strength uncertain, which affects the moisture resistance of the optical cable. The melting point of chromium is 1900 degrees Celsius, and its chemical properties are very stable. It will not rust when placed in air or immersed in water at normal temperature. It has excellent corrosion resistance. Because the surface is easily oxidized to form a passivation layer, it has excellent environmental resistance. Aluminum tape usually shows that the unqualified hot-sticking method is used to replace the qualified film-coated aluminum tape by the casting method, which will also affect the performance of the optical cable.
4. Steel wire, the steel wire in the optical cable is mainly used to protect the optical fiber from mechanical tension. Good fiber optic cables usually use high modulus phosphating steel wire with a short-term tensile force of 1500N or 3000N. The inferior optical cable will be replaced with iron wire or ordinary steel wire with a small diameter. On the one hand, it is easy to rust; on the other hand, because the tensile strength is far less than 1500N, the optical fiber may be strained during construction. The high modulus phosphating steel wire is usually blue-gray, has good durability and is not easy to bend; while the alternative iron wire is usually pinched in the hand and can be bent at will. After a long time, the two ends of the optical fiber box will rust and crack.
5. Loose tube, the loose tube that contains the optical fiber in the optical cable usually uses polymer PBT material. The loose tube such as the reel has high strength, no deformation, and anti-aging. The loose tube of the defective fiber optic cable is sometimes replaced with other materials. The outer diameter is very thin, and it is flattened by pinching it by hand. It is no different from a drinking straw and cannot afford the maintenance of the fiber.
6. Water-blocking tape, water-blocking tape for optical cable or water-blocking yarn is evenly distributed inside the product through the strong water absorption function of super absorbent resin, under the combined action of osmotic pressure, affinity, and rubber elasticity, Super absorbent resin can quickly inhale water several times its own weight. Moreover, the water blocking powder will swell the gel immediately once it encounters water, and no matter how much pressure is applied to it, the water will not be squeezed out. Therefore, the cable core is covered with a water-blocking tape containing water-absorbent resin. In case the outer wall of the optical cable is damaged, some of the superabsorbent resin in the wound will perform a sealing effect due to swelling, which can prevent the entry of water to a minimum. Defective optical cables usually use non-woven fabrics or paper tapes. Once the cable sheath is damaged, the result will be very severe.
7. Aramid, also known as Kevlar, is a high-strength chemical fiber that is currently used most in the military industry. Bulletproof vests are produced from this material. It is DuPont's patented product, and is the main cost component of indoor optical cables. It is mainly used to protect tight-buffered fibers in indoor optical cables from mechanical tension. However, due to the high cost of aramid, the outer diameter of the remnant indoor optical fiber cable is usually made very thin. This can save costs by cutting a few strands of aramid, or use a polyester yarn that looks similar to aramid instead. Polyester yarn can hardly accept any tension. In this way, the fiber is easily strained or broken during laying.
8. Optical fiber, optical fiber is the most central raw material in optical cable. Good optical cable usually uses high-quality fiber cores from major manufacturers. Defective optical cables usually use primary optical fibers and smuggled optical fibers from unknown sources. These optical fibers have messy origins and are difficult to ensure quality. Sometimes single-mode optical fibers are often mixed in multimode optical fibers. Usually, small factories lack the necessary inspection equipment. To make a judgment on the quality of the optical fiber makes it difficult to ensure the quality. In addition, some of them buy short lengths of optical fiber fusion splicing at a low price and make them into optical cables in the future. Because the naked eye cannot distinguish such optical fibers, the questions that are often encountered in construction are: low transmission rate, short interval, large fiber attenuation, inability to connect with pigtails, lack of flexibility, time division of the fiber, and even one fiber at one end. Multimode, but single mode on the other end.
9. Coloring ink, in order to facilitate the distinction of optical fiber during construction, national standards require that both optical fiber and loose tube be colored with obvious colors. High-quality optical cables are colored with high-quality ink according to the specifications, the color is very obvious and not easy to fall. The secondary optical cable will be colored with inferior ink or the refreshing property is not colored. The color of the inferior ink is not obvious and is sometimes easy to dissolve in the fiber paste, making the color indistinguishable. If it is not colored, it will bring great damage to the construction. Convenience.
10. Commodity packaging, optical cables are usually packaged in a wooden or iron-wood reel. The outside of the reel will be sealed with a wooden sealing plate to ensure that the force, bending radius and other conditions of the bulky optical cable during all transportation are within the standard demand scale. Inside. In order to save costs, the defective optical cable usually uses very poor packaging reels, which are almost scattered when they are shipped to the destination. The reels are somewhat cool and do not need to be coiled. The optical cable is shipped after winding it, perhaps with a reel without wood strips.
OPTICO COMMUNICATION (www.fiberopticom.com) focuses on the development of fiber optic network communication product lines and provides a comprehensive solution to the fiber connectivity system components. We supply fiber optic cable and components, such as fiber patch cord, PLC splitter, SFP transceiver, MTP/MPO, CWDM/DWDM, FTTH solution, Data center wiring solution, etc. All the products adopt strict quality standards in the production and inspection, ensuring excellent operation performance and good product stability, and safely and reliably ensuring the long-term use of products.
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