Imagine a world without internet, email, streaming services or social media. Imagine having to write letters or call everyone on a rotary dial phone to communicate. Imagine having to drive to a store to buy anything and everything. Unthinkable, right?
You can thank fiber optics for all these conveniences and more. And while you’re at it, wish the fiber a happy 60th birthday in 2026.
As a materials scientist who has worked with fiber optics for over 30 years, I’ve seen how useful they are, and how scientists are working to improve them.
What are fiber optics?
Fiber optics are hair-thin strands of glass that confine and carry light. Information encoded on that light is how we communicate, watch movies, buy things and stay connected.
To carry information over long distances, the fiber must be extraordinarily clear. The magic behind an optical fiber’s transparency is a combination of material science and manufacturing. As the light journeys along the fiber, little by little, some scatters off the glass molecules themselves and is lost. In modern fiber optics, this loss is so small that light can travel hundreds of miles and still be seen.
Carrying information in the form of light over long distances requires the fiber to act like a mirror. This way it can bounce those bits of light around corners when the fiber is bent, as it might be when strung like electrical wire inside a building.
Optical fibers comprise an inner core surrounded by an outer layer called a cladding, both made from glass. Protective plastic layers surround these glass parts and keep the fiber remarkably strong. The core glass is made from a material that has a slightly higher refractive index than the cladding.
You can think of the refractive index like density. A denser material has more atoms or molecules for its size, so it takes the light longer to travel through it. The refractive index measures this slowing of light inside a material.
In such a design, light undergoes “total internal reflection,” bouncing off the core-clad interface. A remarkable feature of this phenomenon is that the glasses comprising both the core and clad are transparent, but when sandwiched together, light impinging on that interface at certain angles reflects off like a perfect mirror. So how are these special types of glass made?
Fiber optics use total internal reflection to carry light over long distances.
A simple science
In the age of quantum technologies and AI, sometimes sophistication comes best from simplicity.
The optical fibers that wire our world are predominantly made from silicon dioxide, which also makes up beach sand. However, while chemically the same, beach sand is made up of tiny crystals of quartz that have been pulverized by geological weathering and the pounding of ocean waves. These natural origins riddle beach sand with impurities that can absorb light.
