Hello, everyone!
This is the latest article about troubleshooting in PON networks using the in-service OTDR instrument. I will now explain the testing for all three cases I wrote about in the first article. Let's see!
In order to quickly and optimally troubleshoot in PON systems, we must select the appropriate instruments and specific test points. In this case, it is necessary to select the appropriate OTDR instrument, then adjust the appropriate parameters such as fiber type, reflection index, link length, and pulse width. And after that, choose the exact locations for testing. Let us now return to all three cases and see how in-service OTDR testing is done.
PON Case 1. One user has a problem with PON services. In-service OTDR is used, and the test point is the user house. It is necessary to turn off the ONT device and connect the OTDR to the ATB (Access Terminal Box). Adjust the SM fiber to the OTDR and the short pulse width from 3 to 30 ns. The next figure shows this PON case.
PON Case 2. For cascading PON networks, all users on one optical splitter do not have PON services. In this case, in-service OTDR is used, the measuring point is an optical splitter or ATB. It is necessary to set the pulse width from 100 to 300 ns. Optical fiber is SM. It is also required here that OTDR can measure optical splitters, which can input losses of 7 to 10 dB. This PON case is shown in the next figure.
PON Case 3. All users don’t have PON services. In the latter case, downstream measurement is required. This means that it is not necessary to use in-service OTDR, classic OTDR can also be used. Measurement of optical splitters is not required. Pulse widths from 3 to 30 ns should be set on the OTDR. Optical fiber is SM. The next figure shows this case.
This is the end of this topic. I hope you learned something new!
Thank you!
