Details Of The Method Of Fiber Optic Cable Testing


    Green Telecom offers the most comprehensive selection of fiber distribution box, Fiber Optic Splice Closure , fiber optic termination box products to customers in different industries.

    Generally, we test the optical cable in specific projects: connectivity test, end-end loss test, transmit power test and reflection loss test, which are briefly described below.

    1) Connectivity test: Connectivity test is the simplest test method. Just introduce light at one end of the fiber (such as a red pen) and look at the other end of the fiber to see if there is light flash. The purpose of the connectivity test is to determine if there is a breakpoint in the fiber. This method is used when purchasing fiber optic cables.

    2) End-to-end loss test: The end-end loss test adopts the plug-in test method. Using a power meter and a light source, the reference power value is tested first at a certain position of the fiber under test, and then Perform an end-to-end test and record the signal gain value. The difference between the two is the actual end-to-end loss value. Using this value compared to the F D D I standard value, it is determined whether the end-to-end loss test is effective for the connection of the cable. The operation steps are two steps: the first step is a reference metric (PI) test to measure the loss value P 1 from the known source to the directly connected power meter; the second step is to perform the metric (P 2 ) test, the measurement from Transmitter to receiver loss value P 2 . The end-to-end power loss A is the difference between the reference metric and the actual metric: A = P 1 - P 2 .

    3) Transceiver power test: Transceiver power test is an effective method to determine the fiber link of the cabling system. The equipment used is mainly the fiber power tester and a jumper cable. In practical applications, the two ends of the link may be far apart, but as long as the optical power of the transmitting end and the receiving end are measured, the status of the optical fiber link can be determined. The specific operation process is as follows: Remove the test fiber at the transmitting end and replace it with a jumper. One end of the jumper is the original transmitter, and the other end is an optical power tester, so that the optical transmitter works, and it can be on the optical power tester. The optical power value of the transmitting end is measured. At the receiving end, the original jumper is replaced by a jumper cable, and the optical power tester is connected. When the optical transmitter of the transmitting end is working, the optical power value of the receiving end can be measured. The difference between the optical power values ​​of the transmitting end and the receiving end is the loss generated by the optical fiber link.
    4) Reflection loss test: Reflection loss test is a very effective means of fiber line maintenance. It uses a fiber optic time zone reflectometer (O T D R ) to complete the test. The basic principle is to use the time difference between the incoming and reflected light to determine the distance, so that the location of the fault can be accurately determined. Although the F D D I system acceptance test does not require measurement of cable length and component loss, it is also very useful data. O T D R injects a probe pulse into the fiber and estimates the length of the fiber based on the reflected light. The O T D R test is suitable for fault location, especially for determining where the cable is broken or damaged. The O T D R test documentation provides important data for network diagnostics and network expansion. The first method and the third method are more common.

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