Hello everyone!
In last two articles about OLANs, I will finish this theme. Now, I will explain troubleshooting in OLANs. Troubleshooting this type of optical network is very complex and complicated, especially for passive optical LAN. Let's started.
FTTD uses multimode fiber – OM2, OM3 or OM4, FTTO and passive optical LAN uses singlemode fibers – OS1 or OS2 – low water peak fibers. SM fibers use prepolished/splice optical connectors or factory terminated optical connectors. MM fibers use adhesive/polish optical connectors or prepolished/splice connectors. FTTO and passive optical LAN use APC (Angled Physical Contact) optical connectors, because, the big problem is reflectance. FTTD and FTTO use two fibers, passive optical LAN uses one fiber for both directions. Only passive optical LAN has optical splitters.
FTTD system use VCSEL 850 nm as light source, on the other side, FTTO and passive optical LAN uses FB and DFB lasers for 1310 nm and 1490 nm.
Documentation is very important for maintenance and troubleshooting. Documentation is especially important for OTDR instrument measurements. Often, without documentation, it is very difficult to find a problem or it takes a long time.
Troubleshooting in OLAN consists:
Problems with optical connectors,
Measuring insertion loss,
Testing active devices, and
OTDR testing.
Problems with optical connectors
Optical cables of OLANs have optical connectors. The first problem can be optical connectors. We must not mix connectors. For example, we have SC connectors: MM (beige), SM PC (blue), SM APC (green).
After
that, we have to constantly check and clean the optical connectors.
Both when measuring and when connecting. Dust is all around us.
Connectors can become dirty and cause great weakening and problems.
Also, dirty connectors can be damaged. For visual inspection, we can
use an optical microscope. Today, there are many modern microscopes
for checking the surface of optical connectors. For cleaning, there
are many methods and tools. The most popular cleaners are one-click
cleaner for 2.5 mm and 1.25 mm ferrules.
For more information about visual inspection and cleaning optical connectors, see these articles: Troubleshooting process for dirty optical connectors (1-3).
I will continue to explain this theme in the next article >> OLANs (6): Troubleshooting in OLANs
Thank you!
