As we all know, optical cable splicing and splicing is an extremely meticulous work, and it is all too familiar to those who are engaged in this industry. However, for beginners, it may not be clear what is fiber optic cable splice splicing. Now let's talk about what is optical cable splice splicing in detail, and what should be paid attention to when optical cable splice and splicing.
What is fiber optic cable splice
The connection point of optical fiber splicing is called optical fiber splice, which has a great influence on transmission quality and maintenance cost. If the quality of optical fiber splicing is not high, the loss of one optical fiber joint may be equal to the transmission loss of 500m-1000m optical fiber. Optical fiber splicing requires small additional loss of optical fiber splices, high reliability of the splices, good mechanical properties, and long-term stability of characteristics; on-site construction requires simple operation, short connection time, and low cost.
What should be paid attention to when connecting and splicing optical cables
1. Preparation of the end face
The preparation of the fiber end face includes the steps of stripping, cleaning and cutting. A qualified fiber end face is a necessary condition for fusion splicing, and the quality of the end face directly affects the quality of fusion splicing.
1.1 Stripping of optical fiber coating
Master the three-character stripping method of smooth, steady and fast. "Flat" means to keep the fiber flat. The thumb and index finger of the left hand pinch the optical fiber to make it horizontal, and the exposed length is 5cm. The remaining fiber is naturally bent between the ring finger and the little finger to increase the strength and prevent slipping. "Stable" means that the fiber stripping pliers should be held firmly. "Fast", that is, the fiber stripping should be fast. The fiber stripping pliers should be perpendicular to the optical fiber, tilted inward at a certain angle, and then lightly clamp the optical fiber with the jaws. The right hand will forcefully push it out along the optical fiber axis. The whole process To be natural and smooth, in one go.
1.2 Cleaning of bare fibers
The cleaning of bare fibers should be performed in the following two steps.
1) Observe whether the coating layer of the stripped part of the fiber is completely stripped, if there is any residue, it should be stripped again. If there is a very small amount of coating that is not easy to peel off, you can use a cotton ball to dip an appropriate amount of alcohol, dipping it, and gradually wipe it off.
2) Tear the cotton into small fan-shaped pieces with a flat surface, dip a little alcohol (it is advisable to pinch two fingers together without overflowing), fold it into a "V" shape, clamp the stripped fiber, and wipe the fiber along the axis of the fiber. Once successful, a piece of cotton should be replaced in time after 2-3 times of use, and different parts and layers of cotton should be used each time, which can not only improve the utilization rate of cotton, but also prevent the two pollution of fiber detection.
1.3 Cutting of bare fibers
Cutting is the most critical part in the preparation of optical fiber endfaces. Precise and excellent cutters are the foundation, and strict and scientific operating specifications are the guarantee.
1) Choice of cutter
There are two kinds of cutters: manual (such as Japan CT-07 cutter) and electric (such as Ericsson FSU-925 cutter). The former is simple to operate and has reliable performance. With the improvement of the operator's level, the cutting efficiency and quality can be greatly improved, and the bare fiber is required to be shorter, but the cutter has higher requirements on the ambient temperature difference. The latter has higher cutting quality and is suitable for operation in cold conditions in the field, but the operation is more complicated, the working speed is constant, and the bare fiber is required to be longer.
Skilled operators should use a manual cutter for fast optical cable connection or emergency rescue at room temperature; on the contrary, for beginners or when working in colder conditions in the wild, use an electric cutter.
2) Operating Specifications
Operators should be specially trained to master the essentials of action and operating specifications. First of all, clean the cutter and adjust the position of the cutter. The placement of the cutter should be stable. When cutting, the action should be natural and stable, not heavy or urgent, to avoid the occurrence of bad end faces such as broken fibers, bevels, burrs, and cracks. In addition, learn to "play the piano", reasonably distribute and use your right fingers, make them correspond and coordinate with the specific parts of the cutter, and improve the cutting speed and quality.
3) Beware of end face pollution
The heat shrinkable sleeve should be penetrated before peeling, and it is strictly forbidden to penetrate after the end face is prepared. The cleaning, cutting and splicing time of bare fiber should be closely connected, and the interval should not be too long, especially the prepared end face should not be placed in the air. When moving, handle it with care to prevent it from rubbing against other objects. During the connection, according to the environment, the "V"-shaped groove, pressure plate, and blade of the cutter should be cleaned to prevent the end face from being polluted.
2. Optical fiber fusion
Optical fiber fusion splicing is the central part of the splicing work, so high-performance fusion splicer and scientific operation in the fusion splicing process are very necessary.
2.1 Selection of fusion splicer
The fusion splicing equipment with suitable battery capacity and precision should be equipped according to the requirements of the optical cable project. According to the author's experience, Japan's FSM-30S arc fusion splicer has excellent performance, stable operation, high welding quality, and is equipped with dustproof and windproof cover, large-capacity battery, and is suitable for various large and medium-sized optical cable projects. The Siemens X-76 fusion splicer is small in size, easy to operate, equipped with a simple cutter, and the battery and the host are two into one, which is easy to carry, slightly less accurate than the former, and has a smaller battery capacity, which is suitable for small and medium-sized optical cable projects.
2.2 Welding procedure
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 welding should also be cleaned in time? "V" groove, electrodes, objective lens, welding chamber, etc., and observe whether there are air bubbles, too thin, too thick, virtual melting, separation and other undesirable phenomena in the welding at any time, and pay attention to the OTDR tracking and monitoring results. , timely analyze the reasons for the above-mentioned undesirable phenomena, and take corresponding improvement measures. If the virtual fusion phenomenon occurs many times, you should check whether the materials and models of the two optical fibers to be spliced match, and whether the cutter and the fusion splicer are polluted by dust, and check If there is no problem with the oxidation of the electrode, the welding current should be appropriately increased.
3. Disc fiber
Coiling fiber is a technology and an art. The scientific method of coiling fiber can make the fiber layout reasonable, the additional loss is small, can withstand the test of time and harsh environment, and can avoid fiber breakage caused by extrusion.
3.1 Fiber Reel Rules
1) The fiber is coiled along the loose tube or the branching direction of the optical cable. The former is suitable for all splicing projects; the latter is only suitable for the end of the main optical cable, and it is one in and multiple out. The branches are mostly small logarithmic cables. The rule is to reel the fiber once every time after splicing and heat shrinking one or several optical fibers in loose tubes, or optical fibers in a sub-technical direction optical cable. Advantages: It avoids the confusion of optical fibers between loose optical fiber tubes or between different branched optical cables, so that the layout is reasonable, easy to install, easy to disassemble, and more convenient for future maintenance.
2) Take the heat-shrinkable tube placement unit in the reserved tray as the unit to coil the fiber. This rule is to coil the fiber according to the number of heat-shrinkable tubes that can be placed in a small placement area in the reserved tray in the splice box. For example, the GLE type barrel splice box, in actual operation, every 6 cores is a plate, which is extremely convenient. Advantages: It avoids the unevenness of the same bundle of optical fibers caused by different placement positions, difficulty in coiling and fixing, and even sharp bends and small circles.
3) In special cases, such as optical splitters, add/drop pigtails, pigtails and other special devices in the connection, it is necessary to first splicing, heat shrinking, and coiling ordinary optical fibers, and then deal with the above situations in turn. disc operation to prevent an increase in additional losses caused by squeezing.
3.2 The method of coiling fiber
1) First the middle and then the two sides, that is, place the heat-shrinked sleeves in the fixing grooves one by one, and then deal with the remaining fibers on both sides. Advantages: It is beneficial to protect the optical fiber contacts and avoid possible damage caused by the coiled fiber. This method is often used when the optical fiber reserved disk space is small and the optical fiber is not easy to coil and fix.
2) Start the fiber coil from one end, that is, start from the fiber coil on one side, fix the heat shrinkable tube, and then process the remaining fiber on the other side. Advantages: The placement position of the effective copper pipe can be flexibly selected according to the length of the residual fiber on one side, which is convenient and fast, and can avoid the phenomenon of sharp bends and small circles.
3) Handling of special cases, such as individual fibers are too long or too short, they can be coiled separately at the end; when there are special optical devices, they can be treated separately. If they are co-coiled with ordinary fibers, they should be coiled It is placed lightly on the ordinary optical fiber, and a buffer pad is added between the two to prevent the fiber from being broken due to extrusion, and the pigtail of the special optical device should not be too long.
4) According to the actual situation, a variety of graphic fiber coils are used. According to the length of the remaining fiber and the size of the reserved disk space, coil it naturally according to the trend, do not pull it hard, and flexibly use circle, ellipse, "CC", "——" various shapes of coil fiber (note that R≥4cm), as far as possible Maximize the use of reserved disk space and effectively reduce the additional loss caused by fiber disks.
4. Ensure the quality of optical cable connection
Strengthening the monitoring of OTDR is of great significance to ensure the splicing quality of optical fibers and reduce the additional loss caused by the coiled fibers and the damage that may be caused to the optical fibers by the sealing box. In the whole continuous work, the four monitoring procedures of OTDR must be strictly implemented:
1) Real-time tracking and monitoring of each core fiber during the fusion process to check the quality of each fusion point;
2) After each coiled fiber, conduct an example inspection on the coiled fiber to determine the additional loss caused by the coiled fiber;
3) Before sealing the splicing box, conduct a unified test on all optical fibers to find out whether there is any leakage and whether the optical fibers and connectors are squeezed between the optical fiber reserved disks; 4) After sealing the box, perform final inspection on all optical fibers to ensure Check the enclosure for damage to the fiber.
Regarding what is optical cable splice and splice and what should be paid attention to when optical cable splice and splice, the editor today will explain to you here first. In fact, the optical cable splicing and splicing requires the operator to observe carefully, consider carefully, and operate in a standardized manner in the aspects of end face preparation, fusion splicing, and fiber coiling. In short, in the work, it is necessary to cultivate a rigorous and meticulous work style, diligently summarize and think, in order to improve practical operation skills, reduce connection loss, and comprehensively improve the quality of optical cable connection.
