How to choose a right OTDR for fiber optical network


Choosing the right optical testing equipment not only solves find right OTDR for network solutions, but also helps professionals work efficiently, and increase fiber optical network reliability. And also show our mini OTDR specification with you.

The Key of OTDR specification:


SM: single-mode: 1625nm or 1650nm/1490nm/1310nm/1550nm

MM: muti-mode: 850nm/1300nm

Filtered 1625 nm or 1650 nm for in-service troubleshooting of SM

1490 nm wavelength for FTTH systems (optional — test can be performed at 1490 nm, but a common recommendation is to test at 1550 nm to minimize additional investments)

1310 nm and/or 1550 nm and/or 1625 nm wavelengths for SM

850 nm and/or 1300 nm wavelengths for MM

Dynamic Range

The dynamic range is an important characteristic since it determines how far the OTDR can measure.

Dead Zones

The event dead zone (EDZ) is the minimum distance where two consecutive reflective events, the shorter the better

The attenuation dead zone (ADZ) is the minimum distance after a reflective event, the shorter the better


The relationship between dynamic range and a dead zone is directly proportional. To test long fibers, more dynamic range is needed so a wide pulse of light is required. For short distances, short pulsewidths should be used to reduce the dead zones.

What's your application in fiber optical network?

These are the questions to answer before looking for an OTDR:

1-What kind of networks will you be testing? LAN, FTTH/PON, metro, long haul?

2- What fiber type will you be testing? Multimode or single-mode?

3- What is wavelength and dynamic range you are looking for? ( What is the maximum distance you might have to test? 700 m, 25 km, 150 km? )

4- What kind of fiber optics communications test will you perform?

Data Infrastructure, troubleshooting?

OTDR is very important testing equipment for fiber optical network Data Infrastructure. When choosing your OTDR, first to figure out the applications that the OTDR will be used for, and then check the OTDR’s specification to see if it is suited to your applications. And don’t forget to consider those elements we stated in this article. Hope it would help when you hesitate to make your decision.

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