We all know that fiber optic network is based on the fibers which need many cares to use and store. And it is likely to cause lots of troubles in the network performance if the fibers are not in good protection or operation, this post conducts a detailed analysis of the reasons for one of the most common problems in fiber optic network, more than that, you will also find a way to prevent your fiber optic network from any troubles.

Fiber optic network…

Why does your fiber optic network get slow and easy to be off-line? Here are a few reasons:

Fiber optic cable being bent causes power attenuation

First of all, the fiber optic cable would be the reason you should think about first. In many families, people would coil the fiber optic cable in order to let the environment clean and tidy, this may not affect anything unless the fiber gets bent too much like over 30°. When the fiber gets bent too much, the internal optical signal could not fulfill the total refraction, and light spill would happen so that the power attenuation caused. By twining the fiber cable around the fiber optic modem, it is found that the optical power attenuation is about 2dBm per loop; if the fiber is harder, the attenuation would reach up to 5dBm. There must be optical power shortage problems after more loops.

When tidying the fibers, we can get it be like a disc with a diameter of over 10cm. If the fiber is not so long, it can be stored in the slot of the bottom of the fiber optic modem.

Fiber optic tap

Image source: https://upload.wikimedia.org/wikipedia/commons/thumb/f/fc/Fiber_optic_tap.png/1200px-Fiber_optic_tap.png

Dust and water vapor, the enemy of the fiber

The environment will also affect the optical power of fiber optic modem. For instance, when it’s the rainy weather, the optical power of the modem may drop down by 10dBm or even higher. The cause of this problem is almost either the joint part of the fiber and the modem got polluted or the joint part has condensation caused by water vapor, therefore, the intension will naturally lower substantially when the light is covered by the condensation or dust during transmission.

What can we do if without fiber cleaning box and other equipment at home? Just need the filter sponge part of a non-smoking cigarette, stain it with a little absolute alcohol, and then unplug the fiber, wipe the top of the fiber and the interface part of fiber optic modem; after the alcohol volatilizes, re-plug the fiber, then check the optical power of fiber optic modem, there may be surprises.

Cold junction & hot fusion, which is more secure?

As the cold junction process is simple, it is mostly used in the large-scale fiber transformation to splice fibers. While cold junction is a way that itself will cause the attenuation of optical power. In practice, due to the quality of the connectors themselves, plus the technical differences of technicians and other factors, all of which will allow the attenuation of optical power increasing dramatically. When having the trouble of optical power instability, you can try to swing about the fiber signal line or re-plug, if the optical power has a substantial change, then you can basically make sure the cause consists in the joint.

In this case, the hot fusion method is undoubtedly a better choice; the connection relies on welding the fiber optic cable and the light guide material of original fiber together to greatly avoid the optical attenuation, poor contact and optical signal interruption caused by the material interfaces.

To summarize these two methods of splicing fiber optic cables, cold junction is likely to cause a series of troubles, while the hot fusion is more stable relatively.

Be careful with the second-hand or inferior fiber optic products

Fiber optics like fiber patch cord, fiber optic transceiver, fiber optic connector is the key and essential parts for an optical network system. There are lots of suppliers selling the fiber optics due to the huge demands; some of the suppliers earn a quick profit by selling the inferior products with a low price, which is actually making a little use. Therefore, a set of quality fiber optic products is important to help build a perfect network system. In the current market, professional and reliable fiber optic providers like Cozlink are also largely available.


A fiber optic network system is complex and involved with lots of devices and cables; any part of them is able to affect the performance of the whole network. Fiber, as the basic and the carrier of transmitting optical signals, it is to network what blood is to the human body. From this post, we can not only learn the reasons and countermeasures to the problem but also the idea to maintain and protect the fiber optic system from any pollution and damage.