The Technology Behind Fibre Optic Internet 

Fibre optic technology, a breakthrough of the 20th century, has played a crucial role in shaping the hyper-connected world we live in today. It can even serve as an earthquake detector. 

But what is the science behind this marvel of technology?

Key Points:

• Fibre optic cables use light, not electricity, to transmit data.
• The cables are made of a core for carrying the light and a cladding to prevent it from escaping.
• Fibre optic technology is immune to electromagnetic interference, providing stable, high-quality communication.
• The principle of total internal reflection ensures that light signals travel efficiently within the cable.
• Depending on the requirement, single-mode or multi-mode fibre optic cables are used.

Data Transmission through Light

Fibre optic cables carry information through pulses of light. When you send an email, stream a movie, or make a video call, the information is encoded into light signals, which then travel through the fibre optic cable at breakneck speeds. This process makes fibre optics fundamentally different from traditional copper cables, which transmit data through electrical signals.

Imagine a strand of your hair. Now, think smaller. The tiny threads that makeup fibre optic cables are even thinner than that! These miniature lines of communication are made from glass or plastic and measure a mere 50 to 62.5 microns in diameter. For comparison, a typical human hair is about 70 microns.

Cores and Claddings

A fibre optic cable is like a miniature highway for light. Its roadways, crafted from super-refined glass, carry light beams across vast distances at unimaginable speeds.

At the heart of this highway, you have the ‘core’. This is the main route where light pulses travel along. It’s surrounded by a protective ‘cladding’, like a guardrail on a road. This cladding does more than just protect, though. It’s designed to keep the light inside the core, bouncing it back in whenever it tries to escape. 

This ping-pong game of light is what scientists call ‘total internal reflection’.  It keeps the light travelling along the fibre optic cable, allowing data to zip across oceans, continents, and into our homes and businesses.

Interference-Free Communication

Instead of using electrical signals, as is the case with conventional metallic cables, fibre optics use light signals to communicate data. Now, this isn’t just a cool sci-fi movie trick. It has some real-world advantages. The first is an immunity to electromagnetic interference (EMI) and radio frequency interference (RFI).

Think about when you’ve experienced static on a call or your internet slowing down during a thunderstorm. Electromagnetic interference is a common issue with electrical signals and copper-based connections.

Because they are made of dielectric (insulating) materials, like glass or plastic, fibre optics are impervious to such disturbances. Whether a thunderstorm is brewing or a blizzard is howling outside your window, they deliver high-quality communication consistently.