Fiber optic cable splice failure will repeatedly appear in the repaired line, sometimes the same line individual cores in different splice boxes repeatedly broken fiber caused by line failure. After a long and careful analysis, summarizing the following main reasons, and giving the method of prevention, I hope to help you.
(1) Fiber optic splicing after the line has been through, but the disk fiber and sealed splice box after the line does not work again. This is due to improper handling of optical fibers in the splice box, resulting in broken fibers. At present, the fiber optic splicing machine automation work higher and higher, splicing generally will not have problems. However, the operator may break the fiber in the tray, especially when the fiber tray is fixed by the heat-shrinkable tube, the fiber is easily squeezed off through the heat-shrinkable tube and the contact force of the tray. Therefore, the fiber core must be fixed facing up or down to avoid direct contact between the fiber splice point and the disc. The diameter of the reserved circle should not be less than 4cm, and the length of the fiber optic cable stripping should be greater than 1m, such as the stripping distance is too short, it is not conducive to coiled fiber. In the splicing should try to use the better quality connector box, and do not use small manufacturers’ imitations, imitation products often look like but are not reliable. Its fixed connector cable or fiber optic bundle tube function is not sound or missing, bringing inconvenience to the splice seal, and there is a potential for failure. Should be strictly in accordance with the instructions for joint box sealing operation, tighten the screws with moderate force, so as not to damage the joint box too hard, and prevent the joint box from being immersed in water.
(2) Improper heat shrinkage after fiber splicing leads to air bubbles in the heat shrink tube and even leads to broken fibers. As the fault point has been compressed in the connector, so from the appearance of the cause can not be found, more in the re-fusion of the optical fiber after the troubleshooting, and careful examination to find bubbles in the heat shrink tube. After cooling, the heat shrink tube causes the fiber core without the coating layer to break under pressure. This kind of failure is not easy to find. When conditions allow, maintenance personnel can check whether the core has red light through the red light pen to check. To avoid such failure, a good quality heat shrink tube should be used and the spliced fiber should be naturally straightened into the heat shrink slot. The best is placed in the middle of the heat shrink tank to ensure uniform heat shrinkage. Secondly, the parameters of the fusion splicer should be set reasonably according to the climate. Such as winter and summer heat shrinkage time is different, should belong in winter and short in summer. Should also pay attention again to the heat shrink indicator light off, do not rush to take out the heat shrink tube, and should wait for it to cool completely before taking it out. This not only can avoid hot hands, but also prevent damage to the heat shrink tube, to ensure the strength of the heat shrink tube to protect the fiber optic splice.
(3) Redundant fiber optic cable improperly handled resulting in broken fibers. Whether it is directly buried, pipeline laying or overhead laying of fiber optic cable will have a certain amount of spare capacity at the joint. Finally, in the tray redundant fiber optic cable if the cable has stranded, should pay attention to the stranded cable tray, or the cable smooth. Otherwise, the cable with stranded cable is easy to twist loose sleeve, resulting in broken fiber. Be careful when redundant fiber optic cable at the tray splice box, hold the cable at both ends of the splice box with both hands, if there is a twisting force must follow the trend of twisting tray cable.
(4) Fiber stripping reduces the adhesion of the coating layer and bare fiber resulting in fiber breakage. Fiber coating layer to protect the bare fiber and identify the role of fiber sequence. Splicing personnel is accustomed to peeling off the loose casing with alcohol cotton to clean the outside of the fiber grease, alcohol immersion will lead to a serious decline in adhesion between the fiber coating layer and bare fiber, the coating layer off (i.e., fiber decolorization). This reduces the strength of the fiber, shortens the life of the fiber, and can easily cause fiber breakage. The correct fiber splicing, end processing method is: wipe the fiber with clean toilet paper to remove the grease, and dirt, only slightly before cutting the fiber with alcohol cotton wipe stripped coating layer of the fiber, the stripped coating layer of the fiber length should be less than the length of the heat-shrinkable tube, to ensure that the removal of the coating layer of the fiber can be protected by the heat-shrinkable tube.
(5) Too many joints lead to increased loss throughout the optical fiber cable. Fiber optic cable emergency repair after failure to timely rectification, resulting in the existence of too many joints in a shorter distance. Each blocked cable repair to add two joints, and each joint may be a fault point, each additional joint will increase the fiber loss and possible fault points, and once more than the receiving sensitivity of the optical terminal equipment will be judged as a broken fiber fault. In addition, in the repair of fiber optic cable line failure to pass the main, time is rushed, the quality of splicing is not high, it is also easy to break the fiber hidden danger. Therefore, the line should be remediated after the repair to eliminate the hidden trouble.
(6) Repair the fiber optic cable is not the same manufacturer of the same batch of the same model, resulting in fiber optic cable is not only not easy to splice, but also increase the splicing loss, easy to cause further deterioration after a long time after splicing.