Field Guide · concept

Also known as: optical fiber, fibre

Fiber-optic communication sends data as pulses of light through thin strands of glass, delivering very high bandwidth over long distances with low loss.1

Overview

A fiber carries a modulated beam of light by total internal reflection, so the signal travels for kilometres with little attenuation and — being optical — is immune to the electromagnetic interference that affects copper. Single-mode fiber uses a tiny core for long-haul, high-rate links; multimode fiber has a wider core for shorter runs. Fiber underpins long-distance internet backbones, data-center interconnects, and high-speed Ethernet, where pluggable transceivers (SFP modules) terminate the light into a switch. Compared with coaxial cable, it offers far more capacity and reach.

Trade-offs

Fiber’s bandwidth and noise immunity come at the cost of more delicate cabling and transceivers that cost more than copper ports. For most short LAN runs, copper Ethernet is simpler; fiber earns its place over distance or in electrically noisy environments. The same physics — modulating light instead of an RF carrier — is a cousin of the modulation an SDR like GopherTrunk performs on radio waves.

Sources

  1. Optical fiber — Wikipedia, on fiber-optic transmission. ↩

See also