How to Choose an OTDR?

To ensure the reliability and accessibility of fiber networks, network professionals need a more accurate, simpler and faster way to assess the integrity of the infrastructure. Therefore, choosing the right fiber testing tools is critical, not only to help professionals work efficiently and improve network reliability, but also help improve the reliability and value of the entire network. In this article, we will talk about how to choose a fiber optic OTDR.


What is OTDR?

OTDR stands for Optical Time Domain Reflectometer. It is a device for testing optical fibers. The device operates by sending a series of light pulses into the fiber and recovering light that has been dispersed or reflected back along the fiber point from the same end. It can be used to measure loss, optical distance and optical return loss on a fiber optic link.

What an OTDR measures?

Loss of splices

ORL of link

Reflectance of the connectors

Total fiber attenuation

Why You Need an OTDR?

Fiber testing is an important operation for ensuring that the network is optimized to provide reliable and resilient services without fail. Here are two reasons why an OTDR is required.

Service providers and network operators want to protect their investments in fiber networks. To authenticate their work, installers must use Optical Time Domain Reflectometer to perform bi-directional testing and provide proper cable documentation. Of course, you can use OTDRs to troubleshoot issues like break locations caused by dig-ups.

Premises fiber networks have low loss budgets and little margin for error. As a result, installers must assess the overall loss budget with a light source and a power meter, which is a difficult task. While OTDR can quickly identify the sources of excess loss and confirm that splices and connections are within acceptable limits, it also saves time. Furthermore, it is the only method to pinpoint the exact position of a problem or a break.

Key Specifications of OTDR

Dynamic Range

The overall optical loss that an OTDR tester can assess is determined by this specification, which is the total length of a fiber link that the device can detect. The higher the dynamic range, the wider the range of the OTDR. Inadequate dynamic range impairs the capacity to assess the entire link length as well as the accuracy of link loss, attenuation, and far-end connection loss. It is advisable to select an Optical Time Domain Reflectometer with a dynamic range 5 to 8 dB higher than the maximum loss you may experience.


SM (single mode) fiber links should use 1310nm, 1550nm or 1625nm wavelengths.

MM (mutimode) fiber links should use 850nm or 1300nm wavelengths.

Troubleshooting single mode fiber links should use 1625nm or 1650nm wavelengths.

Systems that use FFTX architecture should use 1490nm wavelengths.

Wavelength and Dynamic Range

How to choose your OTDR?

There are many fiber optic OTDR models for different test and measurement needs, so how to choose the right model? It must be according to your specific needs.

  1. What kinds of networks will you put to the test?

Testing FTTH/PON should use three wavelengths OTDR.

  1. What is the maximum distance you need to test?

Our BD3000 OTDR can test 150 km.

  1. What type of fiber will you be testing? Single mode or multimode?

Single mode fiber should use 1310nm, 1550nm or 1625nm wavelengths.

Mutimode fiber should use 850nm or 1300nm wavelengths.

  1. What is your budget?

Different models of OTDR price will be different because of many factors, if you only need to test short distance, you can use a cheaper OTDR which can test only short distance.

What’s more, the factors like size and weight, trace and result storage, display size, Bluetooth or WiFi connectivity, can also take into consideration.


OTDR is a very important test equipment for fiber network data infrastructure. Choosing the right OTDR to test your network not only enhances its reliability, it also increases the efficiency of your test work and the quality of your documentation. When choosing your OTDR, first figure out what applications will the OTDR use, then check the OTDR’s specifications to see if it is suitable for your application.

Baudcom offers various types of OTDR and test equipment. For more information, please feel free to contact us.

Post time: 2022-05-22


Lomoveishiy – Finland

I needed those to connect my PC on the third floor to have internet access in that room, and ISP installed their modem on the first floor only. After dropping fiber patch cables, plugged in all cables into these media converters at both sides, and link came up instantly. Was much easier than I thought!

Raymond – USA

Great experience – units worked straight out of the box – just needed plug in cables and we were done. I also like the possibility to enable jumbo frames, while we do not have a need for this feature at the current moment it’s great to have this option.

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