Fiber optic cable line common failure phenomena and possible causes of analysis

1, distance judgment when the server room to determine the fault is a fiber optic cable line failure, the line maintenance department should be as soon as possible in the server room to test the faulty fiber optic cable line, using OTDR test to determine the location of the line failure point. 2, the probable cause of the estimation of the curve according to the OTDR test display curve, the initial judgment of the cause of the failure, targeted troubleshooting. According to the fault analysis, non-external force caused by optical cable failure, problems in the splice box is more often, leading to fiber breakage or attenuation increase in the splice box is divided into the following cases: (1) splice box into the water, ice in winter leads to increased fiber loss, and even fiber breakage. (2) the residual fiber in the splice closet in the disk to put shelter in the local bending radius is too small or serious fiber twisting, resulting in greater bending loss and static fatigue, in the 1310nm wavelength test changes are not obvious, 1550nm wavelength test connector loss increases. (3) loose fiber in the fiber tray, resulting in fiber pop-up at the edge of the fiber tray or tray screws are squeezed, serious pressure injury, pressure breaks the fiber. (4) Stripping the coating layer when the bare fiber is injured for a long time after the damage to expand, the joint loss increases with the seriousness of the fiber will cause breakage. (5)When making fiber endface, the bare fiber is too long or heat shrinkable protection tube heating fiber protection position is not appropriate, resulting in a part of the bare fiber outside the protection tube, the connector box by the external force caused by the bare fiber breakage.

3, to find the fault point of fiber optic cable line set When encountering natural disasters or outside construction and other obvious external forces caused by fiber optic cable line blocking, the inspection and repair personnel according to the test personnel to provide the fault phenomenon and the general fault location, along the route of the fiber optic cable line to carefully inspect, it is generally relatively easy to find the fault location. If not for the above circumstances, the inspection personnel will not be easy to find the fault location from the abnormal phenomena on the route. At this point, it must be based on the OTDR measured distance from the fault point to the test end, and the original test data to check, to find out the fault point is in which two markers (or which two connectors) between, through the necessary conversion, to find the fault point of the specific location. If conditions, you can carry out two-way test, more conducive to accurately determine the fault point configuration. 4, the main reasons affecting the accurate judgment of fiber optic cable line obstacle point (1) OTDR inherent bias OTDR inherent bias is mainly reflected in the distance resolution, different test distance deviation is different, in the 150 km test range, the test error of ± 40m. (2) inaccurate fiber optic cable line completion data The error caused by the line construction did not pay attention to the accumulation of information or recorded information credibility is low, all make the line completion data and the actual does not match, based on such information, it is impossible to accurately determine the obstacle point.  (3) Calculation error OTDR measured the distance to the fault point can only be the length of the fiber, can not directly get the cable length and test point to the ground distance of the obstacle point must be calculated to find, and in the calculation due to the value can not be completely consistent with the actual or the use of fiber optic cables stranding rate is not clear, will also produce a certain degree of error.  (4) improper operation of the test instrument error in the cable fault location test, the correctness of the use of OTDR is directly related to the accuracy of the barrier test. For example, improper setting of instrument parameters or cursor settings are not allowed and other factors will lead to errors in the test results.  For example, the length of the remaining fiber in the splice box when the cable is connected, the length of the fiber optic cable at various special points, and the undulation of the fiber optic cable with the terrain, etc., the accuracy of these factors directly affects the accuracy of the location of the obstacle.  5, improve the accuracy of fault location of fiber optic cable lines (1) correct, skilled grasp of the use of the instrument Accurately set the parameters of the OTDR, select the appropriate test range file, apply the instrument's zoom function, the cursor is accurately placed on the appropriate inflection points, such as the inflection point of the fault point, the fiber optic start point and fiber optic end inflection point, so that you can get a more accurate test results.  (2) the establishment of accurate and complete original information accurate and complete fiber optic cable line information is the basic basis for barrier measurement and determination. Therefore, we must pay attention to the collection, organization and verification of line data, to establish a real, credible and complete line data.  (3) the establishment of complete and accurate line data The establishment of line data not only includes many data in the line construction, completion of technical documents, drawings, test records and relay section of the fiber optic backward scattering signal curve pictures, etc., should also be retained when the cable factory manufacturers to provide some of the original data of the cable and fiber optic data (such as the stranding rate of the fiber optic fiber, refractive index, etc.), this information is the foundation of the future obstacle tests and Comparison basis.  (4) keep the barrier test and data on the consistency of the test conditions Fault test should try to maintain the signal of the test instrument, operating methods and instrument parameters set consistency. Because the optical instrument is very precise, if there is a difference, it will directly affect the accuracy of the test, which will lead to the difference between the two tests themselves, making the test results not comparable.  (5) Make the correct conversion To accurately determine the location of the fault point, you must also convert the length of the tested optical fiber to the test end (or a connector point) to the ground length of the fault point.  Test end to the fault point of the ground length can be calculated by the following formula (length in m): (6) the establishment of accurate line routing information, including marking stone (pole number) - fiber length (cable length) comparison table (refer to the Appendix), "fiber length accumulation" and "fiber attenuation". "Fiber attenuation" records, in the establishment of "fiber length accumulation" information, should be measured from both ends of the distance from the end station to each connector, in order to test the accuracy of the results of the test, the test can be used according to the circumstances of the transition fiber. With the acceptance of personnel to collect and record a variety of reserved length, the more carefully registered, the smaller the error in the determination of obstacles.  (7) Flexible testing, comprehensive analysis In general, two-way fault test can be carried out at both ends of the fiber optic cable line, and combined with the original information, the location of the fault point is calculated. Then the two directions of the test and calculation results for comprehensive analysis, comparison, in order to make the fault point of the specific location of the judgment more accurate. When there is no obvious characteristics on the routing near the obstacle point, the specific obstacle point site can not be determined, can also be used in the nearby joints such as measurement, or in the preliminary test of the obstacle point at the excavation, the end station's test instrumentation is in a real-time measurement status, at any time to find the curve of the changes, so as to find the accurate fiber optic failure point.  The above is the common failure phenomena and possible causes of fiber optic cable line analysis, I hope to help you find out the causes of fiber optic cable line failure, timely solution.

2, on the federal electronic products network platform related to the introduction and sales of products brief: federal electronic products network - a professional agent / production / sales of all kinds of [connectors | wiring harness | wire and cable products]; if you have a related [connectors | wiring harness | wire and cable products] purchasing / sourcing needs or would like to buy / to understand which connectors | wiring harness | wire and cable products we can provide solutions, please contact our business staff below; If you have related [connectors | harness | wire and cable products] sales / resources and promotion needs, please click on the ¡¡ Business Cooperation ← ¡" and specialists to discuss!