The optical transmission
has the advantages of light weight, small size, transmission distance, large capacity, small signal attenuation, anti-electromagnetic interference, has been widely used in a variety of network. With the twenty-first century will be the advent of fiber optic cable will certainly constitute the main body of China's network data transmission, telecommunications, cable television and other private network. In the choice of cable, twisted-pair cable and coaxial cable, can be roughly determined by visual inspection and simple test its performance advantages and disadvantages. Understand and select fiber is not so simple, compared with cable, twisted pair cable, coaxial cable, complex structure, a wide variety of materials, in addition to the existing technical parameters, there are many potential factors (materials, production processes, equipment, etc.) the slightest mistake, not to mention two or three decades is no guarantee that life is several years of technological parameters may not be standard. So we build a network, it is necessary cable structure for deep knowledge and understanding of materials, technology, etc., in order to choose a suitable model of high quality fiber optic cable.
Choose different types of fiber optic cable according to the number of cores
The center beam tube, Stranded, skeleton and ribbon cable
structure can be divided into several different uses is not the same structure based on line conditions, the user can make any such request. Geenerally less than 12 cores using the center beam tube, central tube process is simple and costs low (about 15% cheaper than the price of Stranded cable), competitive aerial installation or have a good network of branch trunk pipeline protection; Stranded cable place the center of the strand or single wire to strengthen SZ continued synthetic cable, a cable fiber up to 144 core. Its biggest advantage is waterproof, anti-strong pull, a strong lateral pressure. Can be used for direct sale of land. And easy forked cable part of the fiber, respectively, do not have the entire fiber optic cable breaking, breaking can simply be bifurcated fiber for data communication networks. Cable television network along the additional optical node is favorable; thousands of core ribbon cable core number can be done, it is arranged in rows 4 to 12 core optical fiber to form a ribbon fiber unit, then a plurality of strip unit by a certainarranged in a cable network level fiber optic cable is generally used in the beam tube and two layer continued to.
Choose the appropriate fiber optic cable in accordance with the purposes
According to the use of different fiber optic cable can be divided into aerial optical fiber cable
, buried cable, pipe and cable, submarine cable and metal cable. Aerial cables, high strength, temperature coefficient is small; direct buried fiber optic cable anti-buried, compression, moisture-proof, anti-humidity characteristics, resistance to chemical attack; duct and undersea fiber optic cable will have to water oressure resistance, tension-resistant, waterproof characteristics; metal fiber optic cable can be set up with high-voltage lines, insulation is better, although there is no iron body to strengthen the core but should have a certain tensile strength. Therefore, in the purchase of the cable, the user is selected based on the use of fiber optic cable, and manufacturers request, to ensure that the fiber optic cable using a steady, reliable.
To learn the materials used and production process of scouting manufacturers of fiber optic cable
The cable material selection is related to the fiber optic cable service life. The manufacturing process is an important part of the impact on the quality of the fiber optic calbe, process stability, good quality products not included in the fiber cable production process is basically additional loss, ≤ 0.01dB/km the basic data to measure the level of manufacturers of fiber optic cable manufacturing processes. The cable of the main materials used are: core, fiber optic ointment, the sheath material, PBT (poly-on stupid dicarboxylic acid butylene glycol), they have different quality requirements, the core requires a larger reactive charge, higher signal-to-noise ratio, a lower bit error rate, longer amplifier spacing, higher information carrying capacity, requiring the 1310nm the average loss the <0.34dB/km, 1550mn average loss <0.2dB/km, so to be elected imported high quality core, imported high-quality core Corning, United States, United Kingdom NTUC, Sai Hong, Germany; Fiber ointent is the fiber beam tube is filled with the ointent, its role is to prevent the erosion of moisture in the air fiber,
the second is from the cushioning effect of the optical fiber, buffered fibers by vibration or shocks. Ointment stringent quality requirement, emphasizing the ultra-low hydrogen evolution, to ensure good low temperature properties of fiber optic cable, to prevent "hydrogen loss" resulting in serious damage to the fiber optic cable.
So it should be used in imported fiber ointment quality in the world: Japan SYNCOFX405, 400N series; sheating materials of fiber optic cable has a very important role in long-term reliability, is to determine the cable tension, flattening, bending characteristics, temperature characteristics, resistance to natural aging (temperature, irradiation, chemical etching) characteristics, as well as fatigue characteristics of the fiber optic key.
So should be used in high-density polyethylene material, it has a hardness, tensile compressive properties, the skin is not easy to damage; PBT engineering thermoplastics production secondary coating of the fiber optic cable (beam tube), you must have a high Young's modulus (1600/mm2), low coefficient of line (1.5 x 104), good resistance to chemical corrosion, good processing characteristics, low coefficient of friction and so on. PBT material ferrule tube unit, so that the optical fiber bundle having good resistance to lateral pressure and temperature characteristics. Require a relatively high resistance to hydrolysis, in order to ensure the long life of the fiber optic cable, you must use the hydrolysis-resistant PBT material. Better quality United States celanex200L, EMS, Switzerland, B246081, Germany HOLS 30,013,030; plastic wire should be used to strengthen the core to prevent hydrogen loss. The key technology of the fiber optic cable is excess length control and control hydrogen loss affects two aspects of fiber secondary coating process, the most critical is the excess length control excess length of the size of the beam tube center distance and pitchbeam tube fiber than the length of the beam tube a little longer, different cable structure, the excess length of fiber in the beam tube is not the same, unique means of high-quality fiber optic cable in its manufacturing process and control measurements, to ensure that the secondsub-sets of plastic excess length value and the excess length uniformity is well controlled.
When the fiber optic cable in a high hydrogen molecules, or fiber optic cable material in cable manufacturing, storage and running continuous precipitation of hydrogen, hydrogen molecules gradually from the periphery of the fiber to the fiber core diffusion, prone to loss of hydrogen, hydrogen loss lead to fiber the increase in loss, severe acceleration static fatigue of the fiber, the final fiber break, and shorten the life of the optical fiber.
Fiber ointment cryogenic cone small, will cause cryogenic additional loss increase, the amount of hydrogen evolution is high will cause the fiber loss gradually increases over time, the hydrogen loss. High-quality fiber optic cable manufacturers in the selection of materials and processes can be well controlled hydrogen loss, and fiber optic cable factory measured spectral loss characteristics can be predicted cable attenuation characteristics change over time, to ensure the long life of the fiber optic cable. Manufacturers should be used in order to facilitate the construction, fiber optic cable "vertical arrangement of" method of production, and to establish the appropriate process in the production of files, identified by serial files around the disk to facilitate the construction of sequentially numbered laying, welding maximize their fiber mode the consistency of the field diameter, can greatly reduce the splice loss.
In summary, the optional cable is much more complex than the coaxial cable, and not simply the number of core prices measured by a comparision should be based on the structure of the cable, the selection of raw materials, production technology and technical indicators to comprehensive consideration, Do not use the price is too cheap products, should also do the following aspects:
1. Manufacturers must be passed ISO9002 quality system certification, and wait until the State Administration of Radio Film and Television Network that a valid certificate.
2. And evaluate the manufacturers credit, in recent years, the results and the quality of after-sales service guarantee system.
3. Manufacturer is selected, check the raw materials and production processes, products testing during production staff Mill. The arrival of the goods in accordance with the manufacturers after technical indicators acceptance testing, so as not to cause trouble.