Hello, everyone!
Today's topic is testing FTTA. I will start with the necessary procedures for testing and checking and cleaning the surface of the optical connectors.
Testing is mandatory before installation and after installation. Before installing the optical cable on the drum, test the optical cable. It is necessary to check the optical connectors, then the continuity, IL, and the length of the optical cable. Only after that, we can enter the procedure of installing the optical FTTA cable. After the installation is completed, we must test FTTA cables, again. The reason is possible to damage during installation.
Connector inspection and cleaning
Connector inspection and cleaning are the basis of optical networks. Prior to any connection, the surface of the optical connector must be checked and cleaned. Dust is one of the most common problems in optical networks. Therefore, we need to pay special attention to this.
Dirty connectors introduce attenuation, which in some situations leads to link interruption, and generally always affects the performance of the optical link. Dirt can also damage the optical connectors. Then their replacement is needed. The typical diameter of a dust particle is 2 - 15 μm in diameter and this can lead to significant attenuation or damage to the connector.
Different variants of optical microscopes are used to check the contamination of optical connectors. Today's modern microscopes display a surface connection on the display, on the microscope itself, or on some other device such as a laptop or smartphone. There are 4 zones, of which the most important are 1 and 2. In addition, there is software for analysis that allows you to quickly view and analyze the surface of the optical connector.
The principle of checking the surface of the optical connectors in the FTTA systems is given in the first figure. One technician is on the ground and another technician is at the top of the tower.
If the connectors are found to be dirty, clean them immediately. Different methods and tools are used for cleaning. There is a dry and wet method of cleaning with wipes. However, this is more for fiber optics. Today, one-click cleaners are mostly used for optical connectors. These are specially designed tools for cleaning optical connectors. There are 1.25 mm and 2.5 mm diameter ferrules. A single click cleans the connector. A higher number of "clicks" is not recommended as this leads to static electricity.
The table below gives acceptable values for SM and MM optical fibers.
After the connectors have been checked with an optical microscope and cleaned, further testing of the FTTA system can be continued.
This is the end of this article. In the next article, I will explain IL testing >> Testing FTTA (2): IL testing.
Thank you!
