Tag Archives: Fiber Optics

Understanding Wavelengths in Fiber Optics

The light we are most familiar with is surely the light we can see. Our eyes are sensitive to light whose wavelength is in the range of about 400 nm to 700 nm, from the violet to the red. But for fiber optics with glass fibers, we use light in the infrared region which has wavelengths longer than visible light. Because the attenuation of the fiber is less at longer wavelengths. This text may mainly tell you what the common wavelengths used in fiber optics are and why they are used.


Wavelengths Definition

In fact, light is defined by its wavelength. It is a member of the frequency spectrum, and each frequency (sometimes also called color) of light has a wavelength associated with it. Wavelength and frequency are related. Generally, the radiation of shorter wavelengths are identified by their wavelengths, while the longer wavelengths are identified by their frequency.

Common Wavelengths in Fiber Optics

Wavelengths typically range from 800 nm to 1600 nm, but by far the most common wavelengths actually used in fiber optics are 850 nm, 1300 nm, and 1550 nm. Multimode fiber is designed to operate at 850 nm and 1300 nm, while single-mode fiber is optimized for 1310 nm and 1550 nm. The difference between 1300 nm and 1310 nm is simply a matter of convention. Both lasers and LEDs are used to transmit light through optical fiber. Lasers are usually used for 1310nm or 1550nm single-mode applications. LEDs are used for 850nm or 1300nm multimode applications.


Why Those Common Wavelengths?

As mentioned above, the most common wavelengths used in fiber optics are 850 nm, 1300 nm and 1550 nm. But why do we use these three wavelengths? Because the attenuation of the fiber is much less at those wavelengths. Therefore, they best match the transmission properties of available light sources with the transmission qualities of optical fiber. The attenuation of glass optical fiber is caused by two factors: absorption and scattering. Absorption occurs in several specific wavelengths called water bands due to the absorption by minute amounts of water vapor in the glass. Scattering is caused by light bouncing off atoms or molecules in the glass.

It is strongly a function of wavelength, with longer wavelengths having much lower scattering. From the chart below, we can obviously see that there are three low-lying areas of absorption, and an ever-decreasing amount of scattering as wavelengths increase. As you can see, all three popular wavelengths have almost zero absorption.



After reading this passage, you may know some basic knowledge of wavelengths in fiber optics. Since the attenuation of the wavelengths at 850 nm, 1300 nm, and 1550 nm are relatively less, they are the most three common wavelengths used in fiber optic communication. Fiberstore offer all kinds multimode and single-mode fiber optic transceivers which operate on 850 nm and 1310 nm respectively very well. For more information, please visit fs.com.

The Troubleshooting Of Fiber Optics

Fiber optics once just meet the needs of high performance systems, but now it has widely spread in various types of networks. If you are familiar with Network Cabling, then you will soon find that fiber is a kind of something completely different. Not only because of its installation process is quite different with copper wiring, and troubleshooting methods also have very big differences. Compared with copper wire, fiber optics is more fragile, so there will be some potential failures exist when use.

The Most Common Troubleshootings In Fiber Optics

Any network professionals who have done network troubleshooting are clear that this is a complex process. So know where to start looking for faults is very important. Here are some of the most common fiber failures and the possible factors cause these faults, the information will help users to predict the network faults with bases.

Fiber break is usually due to external physical extrusion or excessive bending;

Transmission power shortage;

The Optical fiber laying distance is too long may cause a loss of signal;

Connector damage may result a loss of signal;

Fiber Optic joints and connectors faults may cause a loss of signal;

The excessive use of fiber optical joints and connectors may cause a loss of signal;

Fiber patch panel or splice tra connection failure;

Generally speaking, if the connection is completely unreasonable, then it may be fiber breakage. But if the connection is intermittent, may be the following reasons:

Poor junction levels or multiple junction times cause serious optical attenuation;

The dust, scratches, fingerprints, humidity and other factors damage the connector;

The transmission power is too low;

Connector errors in the Distribution Cabinet.

Collecting Information

Collecting the fault performance and the basic information of possible causes. Using any available means, the key of troubleshooting is to get valuable information by asking the right questions.

The following are some of the problems should be first asked.

If anyone had moved the fiber (dismantling or reconnect) or moved the PC recently?

Find out whether recently PC is disconnected or be moved is very important. If the fiber optical cable is disconnected from the PC, then it is likely that the cable simply has not been properly connected, or problems occur when reconnection, or the fiber may damage when disconnect.

Whether the device recently was moved?

Most copper network failures are caused by someone walking too fast to the original sticking wall table, or cleaners accidentally move the table to do vacuum cleaning. Moving the table without unplug the network cable, the cable is likely to be excessive dragged, or is held down by table or folded. If such action would damage to a copper wire, then you can imagine what consequences will be brought to the fiber, as it is made ​​of glass.

The vast majority of users are not clear that Fiber Optics Cable will break in the situation of stepped on or bend too much.