How Much Do You Know About Fiber Loopback Cable?

With the widespread adoption of 40G and 100G Ethernet network, cabling system in data centers becomes more and more complicated. Choosing a suitable cabling solution is important, but ensuring the normal operation of optical components is the basic requirement. Therefore, it is necessary to carry out fiber optic testing. On the market, there is an useful tool that can provide cost-effective solution for fiber optic testing application—fiber loopback cable. Have you ever used it? How much do you know about it? This article will guide you to know more about fiber loopbackc able.

Overview of Fiber Loopback Cable

Fiber loopback cable is terminated with two connectors on each end of the cable, forming a loop. From the figure below, we can see that there is a black enclosure outside the optical cable. This improved structure is aimed to protect the cable. In addition, this design makes the fiber loopback cable more compact in size and stronger in use. Fiber loopback cable is used to provide a medium of return patch for an optical signal, especially for fiber optic testing applications and network restorations. It can determine where the fault might lie. Similar as fiber optic patch cord, fiber loopback cable can be classified according to fiber type used and fiber optic connector type. So we can find single-mode fiber loopback cable and multimode fiber loopback cable, as well as LC fiber loopback cable, SC fiber loopback cable and MTP/MPO fiber loopback cable on the market.

fiber loopback cable

Application of Fiber Loopback Cable

Fiber loopback cable is often used to check whether fiber optic transceiver operates normally. As we all know, fiber optic transceiver has two ports, a transmitter port and a receiver port. During the testing process, the fiber loopback cable directly routes the laser signal from the transmitter port to the receiver port. Then we can compare the transmitted pattern with the received pattern to make sure the transceiver is identical and has no errors. Take MPO loopback cables for example, they are mainly used for testing parallel optics, such as 40G and 100G transceivers. In addition, the MPO fiber loopback assembly cable is available in 8 fibers, 12 fibers and 24 fibers, which can be applied according to different requirements of testing applications. To have a better understanding of fiber loopback cable’s working way, here is a figure of fiber loopback cable used for testing application for you.

application of fiber loopback cable


Fiber loopback cable is designed for equipment testing, self-testing, engineering, network diagnostics and measurement applications. It plays an important role in troubleshooting in laboratories and manufacturing environments. Besides, it provides a cost-effective way to test the transmission capability and receiver sensitivity of optical network equipment. When choosing a suitable type of fiber loopback cable, we should take the connector type, polish type, and cable type into consideration.


Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.