How Do Fiber Optic Cables Work?

fiber optic cable for internet

The internet is an integral part of our lives. It gives us access to knowledge, information, entertainment, and communication in ways we have never imagined. Such valuable information on the internet is shared through high-quality fiber optic cables. In this blog post, we will explain fiber optic technology by describing the tiny components of a fiber optic and learning about the scientific principles that let fiber optics transmit information at incredible speeds. 

What is a Fiber Optic Cable?

Fiber optics employ light pulses to transmit data. These thin glass or plastic strands offer a revolutionary data transfer approach. A fiber optic cable installer uses these cables to provide significant speed, bandwidth, and transmission distance advantages. Fiber optic cables come in two primary types: single-mode and multi-mode. Single-mode cables offer superior performance over longer distances, while multi-mode wires are more accessible to connect with standard equipment but are better suited for shorter runs.

Components of Fiber Optic Cable

  • Strength Member

 The strength member is a central core made of aramid fibers. Its primary function is to provide crucial tensile strength and structural support. During installation, the cable might experience pulling or bending forces. The strength member ensures these forces don’t damage the delicate glass fibers within. It helps the cable maintain its shape, preventing kinks or bends that could disrupt the light traveling inside.

  • Cladding

Surrounding the strength member is a layer called the cladding, made of glass with a unique twist. It has a slightly lower refractive index compared to the core. The refractive index determines how much light bends through a material. This subtle difference in refractive index is the key to total internal reflection. Light entering the core from the cladding to a particular angle bounces back into the core instead of escaping. 

  • Core

The core’s diameter is vital in information transmission in fiber optic cables. Single-mode cables have a narrow core, allowing a single light mode to transfer. Multi-mode cables have an extensive core, allowing multiple light modes to travel simultaneously.  

  • Coating

A thin layer known as the coating is directly applied to the core. This serves a critical purpose—safeguarding the fragile glass fibers from scratches and other physical damage during handling and installation. The material is typically a polymer like acrylate, chosen for its ability to withstand environmental factors without degrading.

  • Outer Jacket

The outer jacket is made from polyvinyl chloride. It acts as a shield and protects the cable from weather changes or extreme temperatures. The jacket’s thickness and composition can vary depending on which location the cable is installed.

The Working Principle of Fiber Optic Cables

  • The cable is made of glass or plastic fibers, incredibly thin and transparent.
  • The light is transmitted through a central core. A cladding layer surrounds it.
  • The difference lies between the core’s and cladding’s refractive index. It implies how much a material bends the light when it transmits through it. 
  • The core has a higher refractive index in a fiber optic cable than the cladding.
  • When a light ray enters the core from the cladding at a specific angle, it encounters this difference in refractive index. As a result, instead of passing through the cladding and escaping the cable, the light ray bounces back entirely into the core.

Role of Light Sources and Detectors

  • Light Sources: At the transmitting end of the cable, a light source, typically a Light light-emitting diode (LED) or a laser diode, plays a crucial role. These devices convert electrical signals, carrying the information we want to transmit (data, voice, video), into light pulses.
  • Encoding Information: The intensity or frequency of these light pulses can be altered to represent the digital information being sent. Imagine Morse code, where short and long light pulses represent different letters or symbols.
  • Traveling Through the Cable: The encoded light pulses then enter the core of the fiber optic cable and travel through it due to total internal reflection.
  • Detecting the Signal: On the receiving end, a photodetector awaits these light pulses. This device converts the received light signals back into electrical signals. Essentially, it decodes the information that was encoded at the transmitting end.

Types of Fiber Optic Cable Transmission

  • Single-mode fiber optic cables

These cables have a narrow core, allowing only one light mode to travel. This translates to minimal signal distortion and enables them to transmit data over longer distances with exceptional clarity. However, they require specialized and more expensive equipment for connection.

  • Multi-mode fiber optic cables

These cables have a more comprehensive core, allowing multiple light modes to travel simultaneously. This makes it easier for them to connect with standard equipment but also leads to higher signal distortion. A fiber optic cable installer uses these cables within buildings or data centers for shorter distances.

Advantages of Fiber Optic Cables

High Bandwidth

High bandwidth makes sending significantly larger volumes of data possible than those sent in conventional transmission. This means a fast browsing experience, seamless video streaming, and rapid downloads of big files.


Copper cables used for further distances are heavy and bothersome. These make them cumbersome and costly to install, primarily when there is limited space. The lightweight nature of fiber optic cables can be noted. This lightweight ability of the dismounts makes them ideal for long-range deployment and application.


Due to their larger diameter, they require more space for efficient bundling. Fiber optic cables, with their smaller size, are true space savers. This allows for more cables to be bundled together in a smaller area.

Long Transmission Distances

Fiber optic cables boast minimal signal loss over vast distances. This makes them the perfect choice for applications where data must travel far without losing integrity, like connecting remote locations or undersea communication networks.

Experience the Difference of Fiber Cabling By Network Drops

Traditional copper cables need help keeping up with this generation’s massive capacity for data transmission. Release the full potential of your internet speed with Network Drops fiber optic cabling solutions. We use high-quality wiring materials for installation and ensure regular maintenance and repair. Contact us today to discuss your requirements and take the first step toward building a fully future-proofed network. 


Q1. How do fiber-optic cables transmit data with greater reliability?

Information is transmitted using light pulses instead of electricity in fiber optic cables. Compared to light, electrical signals carried by copper cables weaken with distance.

Q2. How does fiber optic internet connect to your house?

A fiber optic cable installer usually employs a set of technologies. A fiber optic cable from the service provider’s network goes to the termination point near your home. This point can be placed atop a telephone pole or under the ground. 

Q3. How do fiber-optic cables transmit data so quickly?

Light flies very quickly within the core of a fiber optic cable. The data could be transmitted faster than electrical signals in copper cables. Fiber optics show nearly no signal loss, resulting in their ability to transmit data at remarkable rates.

Q4. How to install fiber optic cable?

The installation requires a specialized fiber optic cable installer and tools because these are natural thin glass fibers. It is highly recommended that dealing with professionals help with the procedure.

Q5. What are the two characteristics of fiber optic cable?

Data can be transmitted via light waves rather than electric signals. Moreover, they generally support higher data transmission than copper cables.