The optical cable is composed of cable core, reinforcing steel wire, filler and sheath, and waterproof layer, buffer layer, insulating metal wire and other components according to the need.
1. Filling ointment. It is mainly composed of fiber paste and cable paste. Under normal circumstances, the fiber paste should fill the whole loose casing, and the cable paste should fill every gap of the cable core under pressure. At present, the fiber paste can be half-filled or less, while the cable paste can only be coated on the cable core, while the cable paste can be filled at both ends without filling in the middle. This will make the fiber can not get good protection, affect fiber attenuation and other transmission performance, poor waterproof performance can not reach the national standard, once the cable accident water seepage will lead to the whole link water leakage scrap. Under normal circumstances, even if the accidental leakage of water can be repaired only a section of the water, not the need to replace the entire cable. (National standards require water resistance: three meters of optical cable, one meter of water column pressure, 24 hours of water seepage.) If the ointment with poor performance is used, the above problems will also occur, and the thixotropy of the ointment may be poor, which will cause slight bending loss of the optical fiber and unqualified transmission characteristics of the whole link. If the acid of the oil paste will react with the metal material in the cable to precipitate hydrogen molecules, and the attenuation of the fiber will increase rapidly in case of H, resulting in the interruption of the transmission of the whole link.
2. Outer sheath. Cable sheath not only to adapt to many different complex climate environment, but also to ensure long-term stability (at least 25 years). Optical cable sheath should not only have a certain strength, low thermal deformation, wear, water permeability, thermal shrinkage and friction coefficient, but also strong resistance to environmental stress, good material processing performance. Less use or use bad jacket material although can pass factory acceptance, but because of quality defects after a period of time will appear cracking, seepage, if replaced by recycled plastic high quality polyethylene jacket material is more serious. High quality sheath material made of optical cable, cable skin smooth, bright, uniform thickness, no bubbles, otherwise there will be optical cable skin rough phenomenon, and because there are many impurities in the raw material, a close look can find that the cable skin has a lot of very small pit wow, and because of the thin thickness, the entire outer diameter of the cable will be much smaller than high quality optical cable. Indoor optical cable, generally using high quality flame retardant POLYvinyl chloride, appearance should be smooth, bright, good flexibility, easy to peel; Otherwise, there will be poor skin finish, easy and tightly set fiber, aramid adhesive phenomenon.
3. protection material steel belt, aluminum belt. Fiber optic cable steel belt, aluminum belt is mainly used to protect the optical fiber from mechanical side pressure, moisture and other effects, the better optical cable will generally use chrome-plated steel belt. Inferior optical cable with only one side of the rust treatment of ordinary iron or black leather (no coating steel belt) instead of chrome-plated steel belt, a long time, there will be corrosion in the optical cable, fiber hydrogen loss will be intensified, and because of its easy and sheath separation structure is not a comprehensive bonding layer, moisture retaining performance is also very poor; Some tin-plated steel strip instead of chrome-plated steel strip, tin-plated steel strip surface of the ***, bubbles and so on is inevitable, so in the humid atmosphere and surface condensation or immersion conditions, prone to corrosion, especially under acidic conditions faster corrosion. Tin coating heat resistance is poor, melting point is only 232 degrees Celsius, due to the high temperature of the application of extrusion sheath, the peel strength is uncertain, affecting the cable moisture resistance performance. And chromium melting point up to 1900 degrees Celsius, chemical properties are very stable, at room temperature in the air or immersed in water will not rust, corrosion resistance is very good, because the surface is easy to oxidize passivation layer so environmental resistance is very good. Aluminum strip will generally appear to unqualified hot stick coated aluminum strip instead of ductility qualified coated aluminum strip, which will also affect the performance of optical cable.
4. compressive material steel wire. The steel wire in optical cable is mainly used to protect the optical fiber from mechanical tension. Good optical cable will generally use high modulus of phosphating steel wire, short-term tension of 1500N or 3000N. And inferior optical cable will be replaced by iron wire or ordinary steel wire with a small diameter, which is easy to rust; On the other hand, as the tensile strength is far less than 1500N, the fiber may be strained during construction. High modulus phosphating steel wire is generally blue gray, good toughness, not easy to bend; Instead of iron wire, it can be bent freely and for a long time, and the two ends of the hanging optical fiber box will rust and fracture.
5. Anti-aging loose casing. Fiber optic cable in the loose tube of optical fiber generally use polymer PBT material (polybutylene terephthalate), such a loose tube has high strength, no deformation, anti-aging. The loose sleeve of inferior optical cable is sometimes replaced by other materials, the outer diameter is very thin, pinched flat with the hand, and the drink straw is the same, can not bear the protection of the optical fiber.
With the development of science and technology, optical fiber and cable technology is more and more mature, promoting the integration of the three networks, the Internet of things, mobile Internet, broadband information, wireless WLAN construction. For optical fiber light, it is a medium of network transmission, compared with other media, its transmission capacity is large, will not be affected by electromagnetic interference, has very good confidentiality, and the relay distance is long, greatly saves the use of copper materials, reduces the processing cost, so it can be widely promoted and used.