# [TECH] Optical Fiber Communications

**Optical Fiber Communications** transmits data as light pulses through glass fibers, providing the high-bandwidth, low-loss backbone of the internet and global telecommunications.

## Overview

Charles Kao (1966) showed that glass fibers could transmit light over long distances if impurities were reduced. Corning Glass (1970) produced fibers with 20 dB/km loss — the threshold for practicality. Erbium-doped fiber amplifiers (1987) eliminated the need for electronic repeaters every 100 km. Wavelength-division multiplexing (WDM) allows dozens of different wavelengths (colours) on one fiber, multiplying capacity. Transatlantic fiber cables (1988) replaced satellite links; submarine cables now carry ~99% of international internet traffic.

## Key Actors

- **Companies**: Corning (optical fiber, 1970), AT&T Bell Labs, Ciena (WDM, 1992), Pirelli Cables, NEC, Alcatel-Lucent
- **Inventors**: Charles Kao (1933–2018), Robert Maurer, Donald Keck, Peter Schultz (Corning trio)

## Key Patents

- Maurer, R., Keck, D. & Schultz, P. US Patent 3,711,262 (1973) — low-loss optical fiber

## Economic Value

Global fiber optics market: **\$20 billion/year** (2023, Grand View Research). Optical fiber enables the internet, which contributes ~\$11T/year to global GDP. Submarine cable systems alone carry \$10T/day in financial transactions.

## Notes

Grand View Research *Optical Fiber Market* 2023. **Nobel Prize 2009** to Charles Kao. McKinsey estimate of internet GDP contribution from *The Internet Economy* report.

## What This Enables
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- **[TECH] Internet & World Wide Web** — Optical fiber is the physical backbone carrying ~99% of international internet traffic.
- **[TECH] Quantum Computing Hardware** — Quantum networks distributing entanglement between quantum computers will use optical fiber as the physical channel.
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