Several methods for identifying the advantages and disadvantages of common optical cables

1. Ointment. The ointment mainly includes fiber paste and cable paste. Under normal circumstances, the fiber paste shall fill the whole loose sleeve, and the cable paste shall fill every gap of the optical cable core under pressure. At present, the fiber paste is filled half full or less. Some of the cable paste is only applied outside the cable core, while others are filled at both ends of the optical cable and not in the middle. In this way, the optical fiber will not be well protected, the transmission performance such as optical fiber attenuation will be affected, and the waterproof performance will not reach the national standard. Once the optical cable accidentally seeps water, the whole link will be scrapped. Under normal circumstances, even if there is accidental water seepage, it only needs to repair the water seepage section, and there is no need to start over. (the national standard requires that the water resistance performance is: three meters of optical cable, one meter of water column pressure, and no water seepage for 24 hours.) if the poor ointment is used, the above problems will also occur, and the optical fiber may cause micro bending loss due to the poor thixotropy of the ointment, and the transmission characteristics of the whole link are unqualified; If the ointment is acidic, it will react with the metal materials in the optical cable to precipitate hydrogen molecules, and the attenuation of the optical fiber will increase rapidly when encountering h, resulting in the interruption of the transmission of the whole link.

2. Sheath. The optical cable sheath shall not only adapt to many different and complex climatic environments, but also ensure long-term (at least 25 years) stability. The optical cable sheath shall not only have certain strength, low thermal deformation, abrasion, water permeability, thermal retraction and friction coefficient, but also have the characteristics of strong environmental stress resistance and good material processing performance. Although the less used or poorly used sheath material can pass the factory acceptance, it will crack and water seepage after use for a period of time due to quality defects. It will be more serious if recycled plastic is used to replace high-quality polyethylene sheath material. For the optical cable made of high-quality sheath material, after the cable is completed, the outer skin is flat, bright, uniform thickness and free of bubbles, otherwise the optical cable skin will be rough, and there are many very small pits on the outer skin of the optical cable due to many impurities in the raw material. Moreover, due to the thin thickness, the overall outer diameter of the optical cable will be much smaller than that of the high-quality optical cable. Indoor optical cables are generally made of high-quality flame-retardant PVC, with smooth and bright appearance, good flexibility and easy peeling; Otherwise, there will be poor skin finish and easy adhesion with tight sleeve fiber and aramid fiber.
3. Optical fiber. Optical fiber is the core raw material of optical cable. Good optical cable generally adopts the high-quality fiber core of large factories. Inferior optical cables usually use low-grade optical fibers and smuggled optical fibers with unknown origin. Due to complex sources, the quality of these optical fibers is difficult to guarantee. Sometimes single-mode optical fibers are often mixed in multi-mode optical fibers. However, small factories generally lack necessary testing equipment and can not judge the quality of optical fibers, which makes it difficult to guarantee the quality. In addition, some buy short optical fibers at a low price, and then make optical cables after welding. Because the naked eye cannot identify such optical fibers, the problems often encountered in construction are: low transmission rate, short distance, large optical fiber attenuation, unable to connect with the tail fiber, lack of flexibility, easy to break when winding the fiber, and even one optical fiber is multi-mode at one end and single-mode at the other end.
4. Coloring ink. In order to facilitate the construction of optical fibers, the national standard requires that optical fibers and loose tubes should be painted with bright colors. High quality optical cables are colored with high-quality ink according to the standard, which is very bright and not easy to fall off. Low quality optical cables will be colored with low-quality ink or not at all. The color of low-quality ink is not bright and sometimes easy to dissolve in fiber paste, resulting in color indistinguishability, No coloring will bring great inconvenience to the construction