Almost everything you read, watch and send travels as pulses of light inside strands of glass thinner than a hair. Here's why that's the coolest fact in networking.
Six things about optical fiber that sound made up — and aren't.
The core of a fiber is glass with a slightly higher refractive index than its cladding. Hit the boundary at a shallow angle and you get total internal reflection — a mirror with 100% efficiency, no coating required. The light just keeps bouncing, for kilometers.
The light-carrying core of a single-mode fiber is about 9 µm wide. A human hair is ~70 µm. The strand you could barely see between your fingers can carry tens of terabits per second — more than a small country's traffic.
Dense Wavelength Division Multiplexing sends many colors of infrared light down the same fiber at once — each color its own independent data channel. That's how one strand laid in 2001 keeps getting faster: you don't dig, you add wavelengths. It's also literally what SmartOptics does for a living.
Over 1.5 million km of submarine fiber — enough to wrap the equator ~37 times — carries nearly all traffic between continents. In deep water the cable is only about as thick as a garden hose. Satellites? A rounding error.
Fiber glass is so pure that light loses only ~0.2 dB per kilometer. If ocean water were that clear, you could stand on the surface and see the bottom of the Mariana Trench. Window glass gives up after a few meters; fiber goes 100 km before it needs a boost.
The first live telephone traffic ran through optical fiber in 1977 under the streets of Chicago and Long Beach. The physics was proposed in the 60s — Charles Kao got a Nobel Prize for insisting glass could be pure enough. Everyone said it couldn't. It could.
*as long as it's about light. Photon is a 27-billion-parameter model (Qwen3.8) running on SmartOptics' own NVIDIA H100 in Amsterdam — every answer streams to you over fiber, about fiber.
Photon runs on a $20 launch-week token budget — be curious, but be kind. No accounts, no cookies, no data kept.