Communication optical cable circuit obstacle of screening and treatment method,

cable obstacle for many reasons, with the exception of outside force impact, tapping the obstacle factors and more. Therefore, to strictly control the construction quality, conforms to the operation procedures, strengthen the maintenance, establish a complete, complete and accurate maintenance information, and constantly sum up experience in practice, to quickly find and deal with all kinds of obstacles. Now come to the conclusion that the following methods: malfunction and processing room line terminal obstacles, if the obstacles in the terminal room on obstacles test, due to the OT - DR instrument purification out neat curve, in terminal test can find obstacles fiber core test curve is normal. For accurate positioning, it is necessary to add a section to avoid blind area of the tail fiber, generally not less than 500 m in length, to accurately measure the tail long first degrees, fiber access barriers to test again. Part of the system obstacles blocking if the obstacle is a system, on the premise of exclusion of equipment failure, the refractive index of a precise adjustment of OTDR instrument, pulse width and wavelength, make it the same as the measured the parameters of the fiber core, as far as possible to reduce the test error. Then will measure the distance of the information and maintenance data check, see if the barriers in the junction. If by OTDR curve Fresnel reflection peak of observation points has obvious obstacles ( Fresnel reflex is a special case of Rayleigh scattering, it is a special phenomenon during the refractive index of the fiber mutations) , and data check at close range and a joint, can preliminary judgment for box fiber disorder ( Optical fiber fracture more for mirror sexual fracture, inside the box with the larger Fresnel reflection peak) 。 Repair personnel to the scene, can be further judgement, with room personnel first and then for processing. If the barriers and joint distance is large, the inside the cable for obstacles. This kind of strong concealment of the barrier, if positioning, blind search may lead to unnecessary waste of manpower and material resources, such as directly buried cable of earthwork excavation, such as aerial optical cable to pick a peg to hang a lot of, will extend the obstacle lasted. These barriers can be used to accurately determine the barriers. Using OTDR instrument accurately test the barriers to the adjacent joint point of relative distance ( Long) In the conversion, will test the long cable length ( Long leather) In the conversion, and the skin of the cable length barrier point of the growth of the size, can accurate positioning point location. Specific algorithm is as follows: ( 1) Long long conversion conversion La = ( S1 - S2) / ( 1 + P) 。 Type in La for cable long leather; S1 to test the relative distance of length; S2 for optical cable joint box of unilateral plate length, generally take a 0. 6 to 1. 0; P for the cable of ground shrinkage, different fiber structure varies, same spare cable for testing are available, and also have a factory to provide the index. P=( Sa- Sb) / Sb, Sa for a single cable test long; Sb for a single cable marking the skin of the long length for each size. ( 2) Cable obstacle point long leather Ly = Lb + La size calculation. Ly for the barriers in the type long leather size value; Lb to adjacent joint point of box of fibre-optic cable skin long size, +, - The choice of symbols can be according to the cloth end of the cable don't sure. The value of the identified Ly can determine the specific location of the barriers according to the data. Is not allowed in this way can reduce the engineering materials, instruments and the refractive index of the fiber deviation causes such as the test error, avoid long distance calculation cable length, the test results more accurate. Practice shows that this method is simple and effective. Cable full resistance barriers for fiber optic cable line full resistance barrier, easier to find, is commonly caused by outside influence, can use OTDR detects the barriers and the bureau ( Station) Distance, combine the data maintenance, location to determine the barriers, command patrol personnel along the cable routing to see if there is a construction, whether the aerial cable strain and so on, can generally be found the barriers. If can't find you need using the precise calculation method mentioned above, determine the barriers. Fiber optic attenuation is too large obstacles caused by OTDR system fiber core, if it is found that the disorder is caused by the attenuation space-variant, can judge barrier basic point is located in a layup, mostly caused by bending loss. Remaining fiber optic disk remain inside the box or improper heat shrinkable tube falls off form small circle, such as more than make fiber curvature radius is too small. In addition, the connector box can also cause the water junction barrier. After open the connector box, can further judgment, the normal fiber core around the fingers, and make its curvature radius is too small, this time by OTDR ( 1550海里) There will be a big loss, if the loss point is consistent with the obstacle position of optical fiber attenuation, the barriers to that point. And then take a closer look at optical fiber with and without damage or plate of small circle, if it is a small circle will enlarge, otherwise again processing. Cable barriers can through the above method is rapid and efficient screening and treatment. Through the above analysis, work at ordinary times more attention, many problems, many analysis thinking, grasp the method of doing things will produce work times.