Why is an OTDR test extension wire usually required in the course of optical fiber testing using an OTDR?

Optical Time-domain reflectometer (OTDR) is a necessary optical fiber testing tool for analyzing the performance of optical fibers by using light backscattering technique. It can test fiber loss and locate breakpoints, splices, and connectors in fiber networks. However, there is a“Blind spot” in OTDR, which will affect the accuracy of the test if appropriate measures are not taken. Using OTDR to test the extension line is a common method to reduce the influence of“Blind Zone”.

About OTDR test extension line

OTDR extension wire is similar to optical fiber jumper, there is no fusion joint in the middle of optical fiber, generally placed in the box structure, small size, light weight, easy to carry. In the process of optical fiber testing, the OTDR test extension line is mainly used to make up the OTDR test blind area. How does it work?

As we know, the blind area of OTDR is mainly caused by strong light reflection and pulse width, and it will generally extend hundreds of meters forward from the OTDR as the starting point. The OTDR test extension line is generally used between the OTDR and the circuit to be tested, to ensure that the blind area of the OTDR will only be reflected in the extension line (as shown below) , and will not cause a greater impact on the link to be tested.

OTDR Test Extension Line Guide

OTDR test extension lines come in a variety of packages. The box design is one of the most commonly used and has the advantages of durability and portability. The extension cord has two connectors, one for connecting the OTDR and the other for connecting the circuit under test. When the connection is correct, the OTDR can be used to test the attenuation of the fiber optic link.

The OTDR test extension cord is simple to use, but there are two things to note when using it:

1. In order to ensure the accuracy of the test results, it is very important to test the length of the OTDR Extension Line. In general, the longer the test extension line, the better, ensure that the OTDR test extension line is sufficient to cover the entire blind area of the OTDR.

2. Like fiber-optic jumper, there are different types of OTDR test extension cord connectors. We should select the appropriate test extension cord according to the interface of OTDR and the interface type of the link under test.

OTDR and OTDR test extension line are essential tools in the process of optical fiber test. As the world's leading fiber solutions provider, “Melontel” offers a wide range of otdrs and OTDR test extension cords of different lengths and connector types.