The Basics of Fiber Optic Cables

The Basics of Fiber Optic Cables

Fiber optic cables are the latest and greatest in cable technology, and they are rapidly taking over the world. They allow the fastest data transmissions for the longest distances, making them the ideal cable for telecommunication and Ethernet networking purposes.

However, many people are still not aware of fiber optic cables, what is used to make them, and what are their different types. Let’s discuss these things in some detail to give you a better understanding of fiber optic cables.

Before we start, always remember to consult the fiber optic experts at Communications Solutions Inc. in Jacksonville for the best fiber optic cable solutions in Florida.

The Basics of Fiber Optic Cables

Here are the basics that you should know about fiber optic cables.

What is a Fiber Optic Cable?

Fiber optic cable, also known as optical fiber cable, is a data transmission cable that is unlike most Ethernet or network cables. Instead of using electric current through copper wires to transmit data, it uses pulses of light through flexible, optically pure fibers of glass or plastic.

The use of light pulses for data transmission allows faster data transmission speeds over long distances. This and other benefits of fiber optic cables have made them a popular choice for Ethernet networking and telecommunications in recent years.

To fully understand fiber optic cables, we must first understand the components that make up their structure.

Structure of a Fiber Optic Cable

Here are the main components that make up a fiber optic cable.

  • Core

At the center of a fiber optic cable is a thin glass tube called the core. It is the main component that transports the light pulses for data transmission. The pulses are generated by either a laser or a light-emitting diode (LED).

The size of the core can be as small as 8.3 microns and as big as 62.5 microns, depending on the type of fiber optic cable (more on this later).

  • Cladding

The cladding is a thin layer of glass surrounding the core for protection. It also reflects light into the core resulting in the light waves traveling the distance.

  • Coating 

The coating or sheathing is a layer of thick plastic shield that acts like a buffer between the functioning parts of the cable and the protective layer. The coating is designed to reinforce the core, prevent excessive bending, and absorb external pressures and shocks.

  • Strength Fibers

The strength fibers, also known as the strength member, act as the main protective layer to a fiber optic cable. It varies in nature and can be a gel-filled sleeve or include strands of tough Kevlar. Its purpose is core protection, and it is engineered to withstand excessive crushing and pull forces, especially when installation is taking place.

  • Outer Jacket

The outer jacket is the final layer of the cable, and it protects the core and strength of the cable. The jacket is typically color-coded and often labeled to identify the type of optical fiber inside the cable. These cable jackets also have various fire ratings for fire protection.

The jacket colors include yellow, orange, green, and more. 

Types of Fiber Optic Cables

There are three main types of fiber optic cables with the main difference being the size or diameter of the core.

  • Single-mode

Single-mode fiber optic cables are designed for longer distances; this is enabled by the smaller core diameter between 8.3 and 9 microns. It can carry a single signal over greater distances with low transmission loss.

The long-distance clarity provided by a single-mode fiber means that it is a great option for telecommunication systems. The small core also means there is more space for protective layers, like the coating (sheathing), and a typical single-mode fiber can easily carry signals up to 25 miles.

  • Step-Index Multimode

Multimode fibers can carry multiple signals at once due to their thicker core of 50 and 62.5 microns; however, this harms the distance the fibers can carry the signals.

In step-index multimode cables, the light signals enter at various angles, and each signal transmits data at various rates. These cables are designed for moderate distances but, like all multimode fiber optic cables, amplifiers (repeaters) can be used to error correct and regenerate the light signals over longer distances.

  • Graded-Index Multimode

Graded-index multimode cables are fiber optic cables designed for data transmissions at higher rates for use in places, like data centers that need clear, high-speed data transmissions. This type of multimode cable enables a higher transmission rate due to its core, which is arranged in concentric circles.

It is similar to the rings of a tree trunk. Multiple light signals enter the core and are carried through the rings inside. The outer-most rings carry the signal faster than the inner-most ring. The benefit of this design is that graded-index multimode cables can carry many different wavelengths of light signals at once.

This is what allows it to transmit data at high transfer rates of up to 100Gb.


These were the components and different types of fiber optic cables that make up the basics of fiber optic cables. Knowing the basics will help you better understand these telecommunication and Ethernet networking cables taking the world by storm.

If you live in or around Jacksonville, Communications Solutions Inc. is the place for the best fiber optic cable solutions in all of Florida.

Of course, there is plenty more to learn about fiber optic cables, and if you want to dig in deeper or want the best fiber optic cable solutions for your home or office in Florida, Contact Us Today.



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