How does fiber internet work?
Fiber internet, otherwise known as fiber optic internet, is a type of high-speed internet connection. It works by sending light signals through cables made of long, thin strands of glass. This helps give fiber the tremendous speed and bandwidth that it’s known for—fiber tends to be the fastest and most reliable of all internet connection types.
In this article, we’ll dive deeper into why that is and explore the technology behind the fastest internet connections available. You can also learn more about the basics of fiber internet.
How does fiber internet work?
Fiber transmits data by sending light signals (hence the optic in fiber optics) through cables made of long, thin strands of glass. Each strand is about the thickness of a human hair and is very pure (and thus, highly transparent). Each strand of glass is coated in plastic, giving it a mirror effect that helps preserve signal strength. (1)
The light is produced by lasers that switch on and off to send bits of data. The lasers used for this purpose are capable of blinking billions of times per second, and there may be several lasers of different colors sending signals simultaneously. Since the glass is so pure, it can transmit these light pulses over many miles without losing data—this is why fiber internet connections are capable of such high bandwidth. Fiber optic cables are also more resistant to electromagnetic interference than other types of cables, which helps improve reliability.
This ability to retain information over long distances is in stark contrast to cable and DSL connections. DSL internet uses telephone lines to send signals, just like old-school dialup, while cable uses copper coaxial cable lines. Both of these technologies suffer from information loss that gets worse the longer the signal has to travel.
What are the different types of fiber connections?
Wiring those fancy fiber cables to every single home in an area can get expensive quickly. For this reason, providers sometimes run the fiber lines close to a group of homes and then use “regular” copper coaxial (coax) cable or DSL lines to go the rest of the way. This results in a few different designations for types of fiber access: fiber to the home, fiber to the curb, and fiber to the node.
- Fiber to the home (FTTH): Fiber to the home, also known as fiber to the premises (FTTP), is when the fiber lines run directly to the home or building. This means that your entire connection, from start to finish, runs through fiber lines. If you want the fastest possible internet, this is the way to go (assuming you have a choice).
- Fiber to the curb (FTTC): Fiber to the curb is when the fiber connection runs to a utility box or utility pole near the home (no, not to the actual curb). The remainder of the line is made up of coax cables that send the signal from the “curb” to your home. This of course means that you no longer have a 100% fiber connection, which impacts overall performance. However, the impact should be fairly small, since it’s only a short run of cable.
- Fiber to the node (FTTN): Fiber to the node, also known as fiber to the neighborhood, is when the fiber line runs to a node near a neighborhood or other area. The signal is then dispersed with non-fiber lines to the homes and buildings within a given radius. These connections often use DSL lines to run from the node to the home, which has a noticeable effect on performance—particularly for those who live farther from the node, as they will have longer DSL lines in their signal path.
If you have a choice in the matter—all other factors being equal—fiber to the home is the way to go. Fiber to the curb is not as good, but the short run of copper cable shouldn’t have too much impact on performance. Fiber to the node is definitely the worst of the three. However, all three are generally advertised as fiber connections, so it doesn’t hurt to ask the provider how much of the line is actually fiber.
How does fiber internet compare to DSL and cable?
Fiber internet service comes in all different shapes and sizes, depending on how the provider wants to package its service. However, as a general rule of thumb, fiber is faster and more affordable than other types of internet, including cable and DSL.
While you can certainly find cable packages with competitive speeds, you’ll pay for them—it’s extremely expensive to get multi-gig speeds out of a cable line, and the cost of these packages can reach several hundred dollars per month.
Additionally, fiber has a much higher theoretical maximum speed than cable. Cable connections max out at around 3 Gbps, while fiber can support up to 10 Gbps. While this might seem like extreme overkill for many home users (and it almost certainly is), it's worth noting.
Finally, even with those fast download speeds, cable lacks the upload speeds of most fiber connections. Due to its enormous bandwidth, fiber connections can offer what’s known as symmetrical speeds—upload speeds equal to download speeds.
Other types of service have limited bandwidth and usually prioritize download speeds, as most people find them more impactful. This means upload speeds tend to be around 10% of download speeds (or worse) on cable connections.
DSL rarely compares favorably with even cable services, much less fiber. It’s expensive and slow—the technology simply can’t support the speeds of cable or fiber services.
Fiber is the future
If you have it available, we highly recommend fiber internet. It’s fast and reliable, yet still manages to be affordable—the most important factor for many. Plus, the tech is just cool—we’re talkin’ lasers here.
Check out our roundup of the best fiber providers to find a great fiber plan in your area. Then, read what providers are saying about offering speeds faster than 1 Gbps.
Dave Schafer is a freelance writer with a passion for making technical concepts easy for anyone to understand. He’s been covering the world of gadgets, tech, and the internet for over 8 years, with a particular focus on TV and internet service providers. When he’s not writing, Dave can be found playing guitar or camping with his family and golden retriever, Rosie.
Bri Field has a background in academia, research writing, and brand marketing. She has edited scientific publications, conference papers, digital content, and technical communications. As Assigning Editor, she enjoys ensuring all content is accurate, clear, and helpful. In her free time, you can find her in the kitchen trying a new recipe, out on a hike, or working through her massive TBR list.
Endnotes and sources
1. “How does a fiber optic cable work?” How Stuff Works. Accessed 16 November 2022.