Solution: Yes. Due to the high resolution and no dead zone capabilities of the OBR, users can easily distinguish between different events in a network based on their standard characteristics within an OBR trace. The OBR offers two different graphs - the top graph is a high level view of the entire network and the bottom graph allows you to zoom in on particular features of interest.

The image below shows the top graph of an OBR trace. The first three peaks and last peak are different types of fiber connectors, while the event at 5.5 meters is a tight macro-bend. With an OTDR, you would not be able to distinguish between these different events.

Macrobend in OBR network

Figure 1. A fiber optic network scan from the OBR showing a tight bend. It's difficult to distinguish between a bend and a connector.

However, the OBR gives you the ability to successfully distinguish between connectors and bends by zooming in on the bottom graph. To do so, turn on the vertical cursors in the upper graph and highlight the reflection of choice. Select the calculate button, and it will update the bottom graph with a zoomed-in view of the event. If the event is a connector, you will see a tight, precise event; however, if the event is a bend, it will be a wide, diffuse peak, as shown in Figure 2 and 3.

Bend and connector in fiber optic network

Figure 2. The difference between a bend and a connector in a fiber optic network as shown by the Optical Backscatter Reflectometer. The bend gives a diffuse peak, whereas the connector is a sharp peak. The drop in the blue signal level the top graph is due to the loss of power from the bend. The red trace is the pre-bend trace, and shows no drop. This insertion loss value can also be measured with an OBR.

Macrobend in fiber optic network

Figure 3. A zoomed-in view of a macrobend within a fiber optic network. Notice the width of the event is 3 mm as opposed to the sharp peak that is typical of fiber optic connectors.

It is possible to distinguish between multiple different events due to the OBR's resolution and lack of dead zone - not only do you see loss, but you're capable of knowing what event is causing that loss.

Document ID: 0070612001
Last Update: 06/12/2007

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