Hello everyone!
Today, I will explain how to use markers in the OTDR for measuring attenuation, reflection and distance. Let's go.
OTDR instruments have at least two markers that can be used for optical trace analysis. With the help of markers, we can measure the lengths of individual sections, the attenuation of certain sections or events and the reflection on certain events. These markers are usually called markers A, B, C, D, … or 1, 2, 3, 4, ...
First, the simplest use of markers - measuring attenuation on the optical trace without events. We place markers at the beginning and end of the section we want to measure. We read the attenuation on the horizontal axis and the distance on the vertical axis in the display of the OTDR. As we see in Figure 1.
Figure 1. Attenuation and distance measurement
In this way, we can choose the part of the optical route we want to measure. It is important to set the markers accurately, otherwise, an error may occur.
We can also use markers to measure the attenuation of certain events - fusion splices, mechanical splices, connector pairs, macro bends, etc. We need to put a marker at the beginning and end of the event. We can see these measurements in the next figure. On the left side of figure 2, we can see a measured loss for fusion splice, and on the right side, there is a measured loss for connector pair. It is important to set the markers accurately, otherwise, an error may occur.
Figure 2. Measured loss for fusion splice and connector pair
Using markers, we can also measure the reflection of reflective events - connector pairs, mechanical splices, etc. Place one marker at the beginning of the peak and the other in the middle of the peak. Once we set the markers, the OTDR can calculate the reflection on that event. As shown in the following figure. We need to set the markers carefully so that no error occurs.
Figure 3. Measuring Reflectance
Continued in the next article >> OTDR trace analysis (6)
Thank you!
