Optical fiber is basically a transparent and flexible fiber that is usually made of glass or plastic. By placing one or more of these transparent wires inside several layers of special coating, a fiber optic cable is created. Often, instead of fiber optic cable, the shorter term “fiber optic” is used. Optical fiber, like copper wire, is a platform for transmitting information in computer and telecommunication networks. And of course, optical fiber has an important difference with copper wire: copper wires carry data in the form of electrical signals, but fiber optics carry data in the form of optical signals. For this reason, creating and maintaining fiber optic networks requires different technologies, equipment and infrastructure.
What is optical fiber?
Optical fiber (Fiber Optics or Optical Fiber) basically refers to transparent glass (or plastic) strands inside optical fiber cables. But this phrase can have a wider meaning in the field of communication networks and is also used to refer to technologies and networks based on optical fiber. In this case, “optical fiber” refers to technology and media that deals with the transmission of information in the form of light pulses in transparent glass or polymer strands or fibers. Compared to copper cable, optical fiber has more bandwidth, transmission speed and range. Optical fiber is widely used in internet, cable TV and telephone lines.
Optical fiber structure
Fiber optic cable consists of several strands or strands of transparent glass or plastic. The number of these transparent strands varies depending on the type of cable, and sometimes their number reaches several hundred strands.
Each optical fiber has a core made of glass or transparent plastic, which is actually the path of light. The glass “core” is surrounded by another glass layer, which is called “sheath”. These strings, however many there are, are covered by another protective coating, which is called “shock absorber”. And finally, another layer known as “external cover” protects this entire set. Some optical fibers may also have an intermediate cladding between the sheath and the shock absorber cladding.
They may also have two bumper covers. But in general, the optical fiber structure consists of four main components, which are, in order from the inside to the outside:
Core
Clad
Buffer cover
Outer jacket
How does fiber optic work?
Optical fiber transports data in the form of light particles. Each particle of light is called a photon. Photons travel through the fiber optic cable to be transmitted from one point to another. The optical fiber glass core and sheath each have a different reflection coefficient, depending on which they bend the light at a certain angle. The reflection coefficient of any optical fiber is one of its most important features, which determines how much light is refracted and reflected along the length of the cable. This feature is important in determining the signal range and cable length.
When the optical signals move inside the optical fiber cable, they are reflected from the surface of the core and sheath and proceed in a zigzag pattern along the length of the optical fiber cable. This movement is called total internal reflection. The sheath reflects the light that is reflected from the surface of the core to the outside (on the side of the sheath) back into the core so that the light signals are not lost. Optical signals do not travel at the speed of light, but at 30% slower in optical fiber, because the density of the glass layers does not allow the signals to travel faster. But this speed is much higher than the speed of electrical signals in copper cables.
