How Do Fiber Lasers Work?

If I say fiber optics, chances are you’ll think of high-speed internet. And indeed, by using small strands of optical fiber to transmit light, internet service providers can achieve fast and reliable data transmission.

However, fiber lasers are a very special kind of optical fiber. They do not just transport preexisting laser light. They generate it.

Let’s find out how fiber lasers work.

THE BASICS

CHARGE AND RELEASE

At the center of all optical fibers is the core. This is where the light is contained thanks to total internal reflection.

In the case of fiber lasers, the core (usually silica glass) contains atoms of rare-earth elements, called dopants. These dopants, usually ytterbium or erbium are responsible for generating the desired laser light.

But before they can generate laser light, the dopants must first accumulate energy. This is where optical pumping comes into play.