Hello, everyone!
Today, I will start to explain the loss budget. It is an elementary and mandatory thing during the designing ODN.
In general, when designing an optical network, it is very important to calculate a loss budget. Loss budget represents the total attenuation of the complete optical connection between transmitter and receiver. The value should be such that the system can function. After the realization of the network, the attenuation of the optical link is measured using OLTS and compared with the projected value.
This should not be confused with the power budget. The power budget is the difference between the power of the transmitter and the minimum received power on the receiver so that the system can work properly. I will explain it in one of the following articles.
Figure 1. Loss budget
When calculating the loss budget, it is necessary to take into account the wavelengths of the transceiver, the type of optical fiber, the length of the optical fiber, all fusion splices, connector pairs, mechanical splices, optical splitters, WDM modules, etc. What we have to take when calculating the loss budget depends on the system we need to implement. The most elements and the most complicated systems are PON systems and OLAN systems. They are especially complicated to measure and test.
By calculating the loss budget during network design, we check if the system will work. We need to consider both passive and active network components, meaning as I have already mentioned wavelengths, fiber type, fiber length, etc, and active components such as optical amplifiers. When calculating the loss budget, some of the best values from the specification should not be taken for the attenuation values of the passive components, but the average values should be taken.
And after the realization of the network, we measure to check the loss budget. For these tests, we use OLTS (Optical Loss Test Set) or test source, optical power meter, and referent cables.
This is the end of this article. I will continue to explain this topic in the next article >> Calculating loss budget (2).
Thank you!
