Optical Time Domain Reflectometer (OTDR) is a mandatory fiber optic testing tool which uses light backscattering technologies to analyze optical fiber performance. An OTDR can test the light loss and locate the breaks, splices and connectors in fiber optic network.

However, an OTDR has a “Dead Zone“ which can affect the test results. To overcome the limitation of this OTDR dead zone, an OTDR Launch Box is used.

Basics of an OTDR Launch Box
The OTDR Launch Box has many other names – Dead Zone Box, Pulse Suppressor, Fiber Ring and Fiber Optic Launch Cable. How can an OTDR Launch Box minimize the effect of OTDR dead zone during fiber optic testing?

The dead zone of OTDR is caused by a number of factors including the high return level of reflection and the pulse width emitted from the OTDR – and might extend hundreds of yards from the OTDR. Because the dead zone is the initial length of fiber optic cable just after the OTDR, a length of ‘Dummy Cable’ is used to mitigate the dead zone distance. Thus, the receiver of the OTDR signal will have enough time to settle.

OTDR Launch Box Usage Guide

The OTDR launch box comes in various packages. The box-design is the most commonly used one with the advantage of durability. It has a long spool of optical fiber with a pigtail on two ends. One of the pigtail is for input, which is used to connect with the OTDR, the other pigtail on the opposite end is for output, which is used to connect with the optical fiber under test. After connecting the input end and output end to the corresponding port, the OTDR launch box can be used to test the attenuation of the fiber link.

The using of OTDR launch boxes seems really easy. However, the handling of them should be careful. If you want to get accurate test result of the fiber link the length of the optical fiber inside the OTDR launch box should be long enough to cover the whole dead zone. OTDR launch box is like fiber optic cables, it has different types. And one cannot be used in all fiber link test. The following will tell you how to select OTDR launch boxes.

Which OTDR Launch Box Fit Your Applications?

The selection of OTDR launch box is like selecting fiber patch cable. You should basically consider the fiber type, connector type terminated on pigtails, and the polishing type of the connectors. Another important factor that should be considered is the length of the optical fiber of the OTDR launch box as above mentions. The optical fiber of the OTDR launch box should be longer than the dead zone. Thus, most fiber OTDR launch box can support hundreds or thousands of meters. Kindly visit our OTDR Launch Box page for more details.