Optical fiber splicing is a meticulous work, especially in the aspects of end face preparation, fusion splicing, fiber coiling, etc., requiring the operator to observe carefully, consider carefully, and operate in a standardized way. The following ZR Cable introduces the steps and practical skills for you in detail.
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
For the stripping of the optical fiber coating, it is necessary to master the three-character stripping method of smooth, stable 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 subject to 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 stripper should be held firmly. "Fast" means that the fiber should be stripped quickly. The fiber stripper should be perpendicular to the fiber, tilted upward at a certain angle, and then lightly clamp the right hand of the fiber with the jaw, and then forcefully push it out along the axis of the fiber. 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 optical 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 fiber to be stripped, and wipe the fiber along the axis of the fiber. Once successful, a piece of cotton should be replaced in time after 2 to 3 times of use, and different parts and layers of the cotton should be used each time, so that the utilization rate of cotton can be improved, and the double pollution of fiber detection can be prevented.
1.3 Cutting of bare fibers
The cutting of bare fiber is the most critical part in the preparation of the fiber end face. A precise and excellent cutter is the foundation, and strict and scientific operation specifications are the guarantee.
1) The choice of cutter.
There are two kinds of cutters: manual (such as Japanese CT-07 cutter) and electric (such as Ericsson FSU-925). The former is simple in operation and reliable in 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 manual cutters 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, electric cutters are used.
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, 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 incision, 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 edge 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 link 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
According to the requirements of optical cable engineering, welding equipment with suitable battery capacity and precision should be equipped. According to experience, Japan's FSM-30S arc fusion splicer has excellent performance, stable operation, high welding quality, and is equipped with dust-proof windproof cover and large-capacity battery, which 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 combined into one, easy to carry, slightly less accurate than the former, and the battery capacity is small and 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 "V"-shaped 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 of the OTDR test instrument. As a result, the reasons for the above-mentioned undesirable phenomena were analyzed in a timely manner, and corresponding improvement measures were taken. If 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.
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) Coil the fiber for the unit along the loose tube or the divergent 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 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 branch direction optical cable. The advantage is to avoid the confusion of optical fibers between loose tubes of optical fibers or between different branch 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. It avoids the unevenness of the same bundle of optical fibers caused by different placement positions, difficulty in coiling and fixing the fibers, and even sharp bends and small circles.
3) In special cases, if special devices such as optical splitters, add/drop pigtails, and pigtails appear in the connection, you must first splicing, heat shrinking, and coiling ordinary optical fibers, and deal with the above situations in turn. operation to prevent an increase in additional losses caused by extrusion.
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 commonly used when the optical fiber reserved disk space is small and the optical fiber is not easy to be coiled and fixed.
2) Coil the fiber from one end, fix the heat shrinkable tube, and then deal with the remaining fiber on the other side. Advantages: The copper tube placement position 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 placed at the end and coiled separately; with special optical devices, they can be treated in another coil, if they are co-coated with ordinary fibers, It should be placed lightly on the ordinary fiber, and a buffer liner should be added between the two to prevent fiber breakage caused by extrusion, and the special optical device pigtail 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 residual fiber and the size of the reserved space, coil it naturally according to the situation, and do not pull it hard. You should flexibly use circle, ellipse, "CC", "~" shape coil fiber (note that R≥4cm), try to maximize Make use of the reserved space and effectively reduce the additional loss caused by the coiled fiber.
4. Ensure the quality of optical cable connection
Strengthening the monitoring of the OTDR test instrument is of great significance to ensure the quality of fiber splicing and reduce the additional loss caused by the coiled fiber and the possible damage to the fiber caused by the sealing box. In the whole continuous work, the four monitoring procedures of the OTDR test instrument 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, carry out a routine inspection of the coiled fiber to determine the additional loss caused by the coiled fiber;
3) Before sealing the splicing box, uniformly measure all the optical fibers to find out whether there is any leakage and whether the reserved space of the optical fiber has squeezed the optical fiber and the connector;
4) After the box is sealed, a final monitoring of all fibers is performed to check whether the box is damaged to the fiber.
5 Conclusion
Optical fiber splicing is a meticulous work, especially in the aspects of end face preparation, fusion splicing, fiber coiling, etc., requiring the operator to observe carefully, consider carefully, and operate in a standardized way.
In short, it is necessary to cultivate a rigorous and meticulous work style, diligent in summarizing and thinking, in order to improve practical operation skills, reduce connection loss, and comprehensively improve the quality of optical cable connection.
