Do you know how to choose the ideal fiber optic OTDR?
The fiber optic market has experienced intensified growth in Brazil and Latin America as a whole in recent years. The increasing expansion of FTTH (fiber to the home) networks brings an increase not only in the acquisition of cables and optical equipment, but also in the tools that guarantee the quality of this transmission.
In this sense, one of the essential instruments to provide efficiency and speed to the maintenance of the fiber optic network is the OTDR – optical time domain reflectometer.
You OTDRs are able to certify the performance of new fiber links and detect problems in existing links. It is a measurement tool that can be useful for validating a network and also for identifying a break in the optical cable.
In general, OTDR measurements are used to analyze optical fiber transmission. Therefore, they are essential for mapping link loss in relation to distance.
But how does an OTDR work? And how can this help you ensure a more effective and reliable network?
How OTDR works
Generally speaking, the OTDR emits short pulses of light and sends them through the fiber core, being able to measure the optical signals that return to it as a function of time. Fundamentally, it uses the principle of Rayleigh scattering. In other words, the light that is emitted by the OTDR is reflected back to the equipment. From the moment the reflection is received, the OTDR calculates the attenuation value of the optical cable.
Without the help of this device, mapping each section of the fiber in search of a fault can be a long process and with great operational costs for the internet provider. Although network certification can be done in other ways, Using OTDR as a method is the most agile and accurate way to test optical fibers during installation, maintenance and restoration.
And how do you know which type of OTDR is most suitable?
Contrary to what many believe, the network distance that the equipment can reach is not the only criterion for choosing the best OTDR. There are other equally important parameters.
For example, we can find equipment that works with active fiber, that is, it is not necessary to interrupt the signal to carry out repairs. And there are those that work only with the fiber switched off or without signal, where it is mandatory that the network is turned off for the technician to carry out maintenance.
Some important points to consider:
1- CHOOSE FOR ACTIVE FIBER OTDR
For small providers that are already consolidated and fully operational, it is necessary to opt for an active fiber OTDR. To operate an unlit fiber OTDR, it will be necessary to turn off the PON port related to that section, and this will affect all users connected to it. Therefore, in order not to discontinue services to any user, it is necessary to validate the network while it is fully operational.
2 – AVOID P2P OTDR
Since providers that work with fiber typically opt for the FTTx topology, having splitters in their networks, this P2P equipment is not recommended as it only measures from one point to another. This way, the technician will need to go from box to box, remove the splitter and measure the section in question, which is not the best solution for a PON network. You will need many additional configurations to measure the complete network.
3 – DYNAMIC RANGE
The dynamic range (power) of the OTDR is also important.
It is recommended that you purchase an OTDR of at least 36 dB, as a less powerful one is not capable of measuring networks with a split of 64 or 128 subscribers per PON port.
4 – VISUALIZATION OF RESULTS
Checking the way the equipment displays measurement results is also essential. A simplified image, such as a block diagram view, becomes much clearer, and identifying all splitters and events in a didactic way is the best choice. This type of fiber optic OTDR makes the technician's life easier and does not require complex analyzes on how and where the network is losing power (or how and where events are occurring).
Advantages of using OTDR in your network
When it comes to maintenance, the benefits of this instrument are significant. The OTDR can accurately measure the location where there is an optical cable with a defect or even a break. Furthermore, when certifying the network, the equipment requires a lower maintenance rate and considerably reduces the operating cost for the provider.
OTDRs guarantee the quality of fiber optic transmission. And they prove to be even more useful at fault location in long optical links, like us backbones and metropolitan networks, which are tens of kilometers long.
In short, This is an instrument that helps the provider offer a quality service. By indicating exactly where the events and defects are, the technician can carry out an assessment and repair very quickly. With regard to infrastructure, purchasing the equipment is undoubtedly an intelligent management decision.
To offer an excellent service, it is necessary to know how it works in depth, as well as to value planned management and control over the entire network. Only in this way can your company grow further, with quality.
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