STEM与日常科技·英语30篇（2）

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光纤如何传输网络信号

Optical fibers are hair-thin strands of ultra-pure glass that guide light pulses over hundreds of kilometers without serious loss.
Signals start as electrical data from your router, which a laser converts into rapid on-off flashes of infrared light.
Total internal reflection keeps light trapped inside the fiber’s core, bouncing smoothly along even around gentle bends.
Multiple wavelengths — colors — of light travel simultaneously through one fiber using wavelength division multiplexing (WDM).
Repeaters or optical amplifiers boost weak signals every 80–100 km, restoring strength without converting back to electricity.
At the destination, photodetectors turn light pulses back into electrical signals your computer understands instantly.
Compared to copper wires, fiber carries vastly more data, resists electromagnetic interference, and suffers less signal delay.
A single fiber pair can stream over 10 million HD videos at once — enough for entire cities’ internet needs.
Installation requires precision: bending too sharply causes light leakage, while dust on connectors creates signal loss or outages.
Future upgrades focus on smarter signal processing and hollow-core fibers that may reduce latency further for finance or AI applications.