OTDR (Optical Time-Domain Reflectometer)

What is OTDR?

 An optical time-domain reflectometer (OTDR) is an optoelectronic instrument used to characterize an optical fiber. An OTDR is the optical equivalent of an electronic time domain reflectometer. It injects a series of optical pulses into the fiber under test.

 It also extracts, from the same end of the fiber, light that is scattered (Rayleigh backscatter) or reflected back from points along the fiber. (This is equivalent to the way that an electronic time-domain reflectometer measures reflections caused by changes in the impedance of the cable under test.) The strength of the return pulses is measured and integrated as a function of time, and is plotted as a function of fiber length.

Main functions of OTDR:

1. Fast automatic test

 Automatic test function allows the user not to have to know more details about the equipment operation, test steps become very simple. User only needs to connect in the optical fiber, click “Test” button, then the instrument will automatically set optimal test conditions and eventually give accurate test results, such as the test curve and event lists.

2. Fast curve analysis

 It can find out the event point or failure point in test curve and its location information quickly and accurately test curve, and list all event information in the circuit in the form of event list. This is very helpful for circuit maintenance personnel, not only improves the testing efficiency, but also eliminates the need to learn difficult background knowledge.

3. Powerful document management

 In addition to the ability to store, view, delete the files in the machine, it also provides PCL language-based laser or jet printers to print test reports. Besides, it also utilizes PC software to realize high-speed communications with PC via USB cable.

4. Convenient VFL function

 With visual IR VFL function, it can easily and quickly find the locations of disconnecting points or big loss points in short-distance optical fiber links, so that the maintenance personnel could take measures in shortest time therefore saving a lot of time.

5. Manual test mode

 Users can choose real-time test mode or average test mode according to the testing needs. Real-time test can fast test the dynamic change of optical-fiber links. It is mainly used for the connecting occasions requiring monitoring or observing optical-fiber links at real time.

6. Average test mode

 Average test mode is used to withhold the noise in test curves to the most extent, therefore obtain more accurate testing results. In average test mode, the number of averaging tines will influence the effects of suppressing the noise in test curves. The bigger the number of time is, the effect the time is, but the testing time is to be extended accordingly. Therefore, user should set averaging time based on actual need.

FOT OTDR series

OTDR, OPM, Digital Fusion Splicer

Fiber optical tools series

 FOT OTDR-X000 series portable optical time domain reflectometer (OTDR) is the latest FTTx optical fiber cable-based test instrument. Its features include small size, low weight, elegant appearance, easiness of installation and maintenance, high-capacity built-in battery . It provides multiple built-in test wavelengths and optical testing functions like visual fault locator (VFL). As a product specially designed for FTTx network testing, it provides site technicians with the highest performance and upgrade services.


  • Advanced anti-reflective LCD, display interface is clearly visible in bright light
  • (VFL)Visual fault location function
  • High-speed USB port, waveform file conversion and printing convenience
  • Long-lasting lithium battery, ideal for long-time outdoor construction work
  • Online upgrade function, users do not have to go back to original factory to upgrade the system.

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  1. hello author, I went through the article, good information on main functions of OTDR. Literally essential for the fiber optics maintenance and operation. Connecting damaged Fiber Optics, is a tedious task, fibershot OTDR locate faults in deployed fiber optic networks, for both multimode and single-mode networks, including FTTx PONs.

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