Optical fiber connection methods and matters needing attention
In the face of increasing demand, many users do not conduct certification tests on the installed twisted pair cables, but test them during the network debugging process. When the network can be connected, the installed cables are considered qualified. This approach is not only wrong but very dangerous. Because the network traffic is very low during network debugging, the user does not feel a problem at this time, but when the network traffic is high, it may be difficult to access the Internet.
The fact that the network can be commissioned does not mean that the cable meets the installation standards, nor does it mean that the cable will work correctly when the network is running normally. In addition, at present, most users install Category 5 twisted pair cables, and the network running is 10Base-T, but 10Base-T can run does not mean that 100Base-TX can also run. Therefore, whether the installed cable can support high-speed signals must pass the relevant certification test to prove its performance. Otherwise, it is impossible or difficult to repair the cable when it is upgraded to the high-speed network.
Therefore, the most basic condition for the safe operation of the network is to ensure the safety, reliability and effectiveness of the transmission medium. It is necessary to achieve a high degree of safety and stability of the network wiring connection components and good matching between components, and to reduce the loss of signals as much as possible. As well as providing enough transmission capacity to support the application demands of today and tomorrow. Here, we only discuss fiber-optic networks.
The light conduction tool achieved by the principle of total reflection of light in the fiber made of glass or plastic is connected to the company or home or computer room. Use a switch or other terminal to convert it into an ordinary RJ45 network cable and connect it to the computer, also called LAN. The switch or other terminal automatically assigns IP. The intranet IP needs to be set in the background of the terminal. The default is automatic, and no dialing is required. my country's research and development of optical fiber communication is in a period of ten years of turmoil and is in a closed state. There is basically no way to learn from foreign technologies. It is purely self-exploration. Everything must be done by yourself, including optical fibers, optoelectronic devices and optical fiber communication systems.
As far as the development of optical fibers is concerned, raw material purification, smelting lathes, wire drawing machines, and optical fiber testing instruments and splicing tools must all be developed by ourselves, which is extremely difficult. Wuhan Research Institute of Posts and Telecommunications, taking into account the guarantee that optical fiber communication can eventually be used for economic construction, has carried out comprehensive research. In addition to the development of optical fibers, it has also carried out research and development of optoelectronic devices and optical fiber communication systems, so that my country has a complete optical fiber communication industry.
In the current general optical fiber cabling network, because the technology and quality of the optical fibers used in the wiring are generally stable, the characteristics of optical cables composed of optical fibers and various optical fiber connectors, jumpers, pigtails and other components are relatively stable. And in the actual use of wiring, they are relatively fixed. Below, we analyze and discuss the more commonly used fiber optic connection technologies:
fiber optic connection
1. Splicing method: Optical fiber fusion splicing is a connection method that is widely used at present. Relatively speaking, fusion splicing is a method with high success rate and connection quality, but it should also be noted that the joint after fusion splicing is relatively easy. One of the main factors of damage or failure, since the maintenance operation of the equipment is necessary in the process of use and maintenance, its safety is a problem that we must consider. Before splicing, according to the material and type of the optical fiber, set key parameters such as the optimal pre-melting main fusing current and time and the amount of fiber feeding.
During the welding process, the "V" groove, electrodes, objective lens, welding chamber, etc. of the welding machine should also be cleaned in time. Observe whether there are air bubbles, too thin, too thick, virtual melting, separation and other undesirable phenomena in the welding at any time. Pay attention to the tracking and monitoring results of the OTDR. Timely analyze the causes of the above-mentioned undesirable phenomena and take corresponding improvement measures. If the phenomenon of virtual fusion occurs many times, check whether the materials and models of the two optical fibers to be spliced match, whether the cutter and the fusion splicer are polluted by dust, and check the oxidation status of the electrodes. If there is no problem, the fusion current should be appropriately increased.
For the same batch of fibers, the mode field diameters are basically the same. After the fiber is disconnected at a certain point, the mode field diameters between the two ends can be regarded as the same. impact is minimized. Therefore, fiber optic cable manufacturers are required to use the same batch of bare fibers, continuously produce them according to the required length of the fiber optic cable, and sequentially number and distinguish the A and B ends on each reel, without skipping numbers. When laying the optical cable, it must be laid out according to the number along the determined routing sequence, and ensure that the B end of the optical cable in the front coil is connected to the A end of the optical cable in the next coil, so as to ensure that the connection can be spliced at the disconnection point, and the splice loss value reaches minimum.
2. The method of cold splicing or on-site grinding of optical fiber connectors: Anyone who has been engaged in factory manufacturing and production of optical fiber products should know this very well. On-site grinding and factory manufacturing are two completely different methods that are incomparable. The factory adopts It is a five-step grinding process from coarse to fine by a special grinding machine. It is impossible to adjust the pressure and maintain a consistent manual grinding on site.
Perhaps in the traditional low-speed network in the past, even if the insertion loss and return loss exceed the standard, the connection is unstable, etc., it may be acceptable for network applications, because the optical fiber has enough surplus to absorb the impact of these factors. However, in today's increasingly high-performance network, many indicators and parameters are extremely sensitive, because the link fails to meet the design requirements or is time-consuming and labor-intensive, which makes designers or constructors troubled, and the loss exceeds the network design. Requirements, test failures, etc. occur from time to time. As a result, there are consequences such as delays in construction schedules, design changes or re-planning.
Compared with the traditional optical fiber terminal methods, the pre-connection technology adopts the optical fiber straight-through method, that is, the optical fiber has no connection point. According to the requirements of customers, the products are customized by the factory, and the grinding process is carried out in standard procedures. All technical indicators comply with IEC, TIA and related standards. At this point, the technical indicators far exceed the on-site grinding connectors. At the same time , The optical cable structure is also different from the indoor soft optical cable commonly used in China. In order to ensure that the optical cable has sufficient mechanical properties, its structure is a central bundle of 2 cores to 144 cores. , The oil-filled structure also ensures the environmental and water-blocking characteristics of the optical cable. In the output part of the optical cable, there is no welding or other mechanical connection methods, which eliminates the possible adverse consequences caused by the existence of joints. Optical cable products that may add factors to make network design or construction easier to control.
In addition, because the pre-connection adopts special optical cable branch components, the plug-in structure can firmly fix the optical cable on the special rack to ensure that the 50kg tension distribution box will not be deformed. At the same time, the rectangular card interface can prevent the optical cable during use. The stress is released, so that the optical fiber link between the connectors at both ends is always in a free and slack state, avoiding the performance of the optical fiber due to the extrusion, stretching or twisting of the cable sheath, and ensuring the safety of the optical fiber network and the owner's investment to the greatest extent. sex.
For the majority of engineers, the next content is closely related to the actual project, "how to install the pre-connected optical cable?" At the same time of product development, we specially designed the installation protection tube, its function is to : First, ensure that the optical cable can withstand enough strength when placed in the pipeline or bridge, and the sealed structure ensures the dustproof and waterproof performance during the installation process, so its installation can be the same as in the past construction, and will not affect the optical fiber and optical cable. In case of any damage, the waterproof and protection grades reach IP50 and IP67 respectively.
Finally, the advantages of the pre-connection method are also reflected in the improvement and upgrade of the network. As mentioned above, the rapid changes in the application of the network will inevitably lead to changes and revisions of the network. However, due to the characteristics of the connection method used in the past, in many cases, customers It will be abandoned because the project is too complicated. In the end, the structure of the equipment room may be unreasonable after the expansion, and the use and maintenance will become complicated and cumbersome. The characteristics of the plugging and unplugging of pre-connected optical cables solve this problem very well.
Combined with the above analysis, we summarize several characteristics of the application of pre-connected optical cables:
1) To protect the effectiveness and safety of the owner's investment, the pre-connected optical cable must be customized, which puts forward higher requirements for the integrator's ability to conduct preliminary and actual on-site investigations. The purpose is to fully protect the owner's right to control the project and the right to know the use of products. , to avoid the risk of material waste and project investment.
2) More economical The welding process requires machines, consumables, time and personnel, etc. In general, the pre-connection method does not increase additional costs.
3) Easy to operate, easy to install, save installation time, just plug and play as needed.
4) The loss test has been completed, the quality is stable, the use of reliable pre-connected optical cables is 100% tested by the factory, and no other products are attached during the installation process, and the on-site test is simple.
5) The optical fiber link is fully protected, no fusion splices and bare optical fibers are exposed to the air, and there will be no worries about aging and joint breakage.
6) Easy maintenance and safety The mechanical properties of the pre-connected optical fiber splitter are excellent, and the maintenance or operation process will not affect the normal use of the optical fiber.
7)The splitter of the pre-connected optical cable can be quickly and safely plugged and moved, and reinstalled as needed. Entering the market from pre-connection, it has been applied in the design and construction of optical fiber networks in many telecom operators, finance, education, public security, customs, enterprises, science and technology parks, etc., and has also won high recognition from integrators and end customers. And wide acclaim, make us more confident, we hope that more users can have such an optical fiber network with convenient construction, high security and excellent performance.