---
title: "Optical fiber advantages over coax and twisted pair"
subject: "Data Communication"
chapter: 4
key: "semester_5/data_communication:fiber-advantages"
source: https://www.bctengineer.com/q/semester_5/data_communication/fiber-advantages
site: BCT Engineering
---

# Optical fiber advantages over coax and twisted pair

Data Communication · Chapter 4: Transmission Media

- Asked in: 2074 Asoj, 3 marks; 2069 Chaitra, 3 marks; 2069 Asar, 3 marks (asked 3 times)
- Video: [Lec-10: Types Of Cables in Computer Networks | Coaxial, twisted pair, fibre optic cable](https://www.youtube.com/watch?v=wuI6FGsOFZU) — Gate Smashers
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/data_communication/fiber-advantages
- Whole chapter: https://www.bctengineer.com/md/semester_5/data_communication/chapter-4

## Question

What are the advantages of optical fibers over coaxial cable and twisted pair cable?

## Short answer

Optical fibers offer very high bandwidth (Gbps–Tbps), low attenuation (~0.2–0.5 dB/km) enabling long repeater spans, immunity to EMI and crosstalk, high security, small size and weight, and no electrical hazard, making them superior to coaxial and twisted-pair cables.

## Answer

Advantages of optical fibre over coaxial and twisted-pair cable:

1. **Very high bandwidth and data rate**: a fibre carries Gbps to Tbps; coaxial and twisted pair are limited to Mbps to a few Gbps.
2. **Low attenuation**: about 0.2 to 0.5 dB/km, so repeaters can be 40 km or more apart, against 1 to 9 km for coaxial and about 2 km for twisted pair.
3. **Immunity to electromagnetic interference and crosstalk**, since light is not affected by electrical noise, lightning or nearby power cables.
4. **High security**: tapping a fibre is hard to do without being detected; copper cables can be tapped easily.
5. **Small size and light weight**, with much more capacity per unit area; fibre is also thin and flexible.
6. **No electrical hazard**: no sparks and no ground loops, so it is safe in explosive areas; it is also corrosion resistant.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Fibre bandwidth is
   A. Kbps
   B. Only Mbps
   C. Gbps to Tbps
   D. Same as UTP
   Answer: C. Much higher. (Key point: Bandwidth)

2. Fibre is immune to EMI because
   A. It is thick
   B. It is cheap
   C. It is shielded copper
   D. It carries light
   Answer: D. Light unaffected. (Key point: EMI)

3. Fibre attenuation is
   A. 0.2-0.5 dB/km
   B. 10 dB/km
   C. 50 dB/km
   D. 1 dB/m
   Answer: A. Allows 40 km spacing. (Key point: Attenuation)

## Related in Data Communication

- [Coaxial cable vs optical fiber](https://www.bctengineer.com/question.md?key=semester_5%2Fdata_communication%3Acoax-vs-fiber) — Data Communication, chapter 4
- [Why wires are twisted in twisted pair](https://www.bctengineer.com/question.md?key=semester_5%2Fdata_communication%3Atwisted-pair-why-twist) — Data Communication, chapter 4
- [Optical fiber vs satellite transmission](https://www.bctengineer.com/question.md?key=semester_5%2Fdata_communication%3Aoptical-fiber-vs-satellite) — Data Communication, chapter 4
- [Short note: Multi mode optical fiber](https://www.bctengineer.com/question.md?key=semester_5%2Fdata_communication%3Amultimode-fiber-short-note) — Data Communication, chapter 4
- [Short note: Optical fiber versus STP](https://www.bctengineer.com/question.md?key=semester_5%2Fdata_communication%3Aoptical-fiber-vs-stp) — Data Communication, chapter 4

## Related in other subjects

- [Compare twisted pair, coaxial, fiber](https://www.bctengineer.com/question.md?key=semester_7%2Fcomputer_networks_and_security%3Acompare-twisted-coax-fiber) — Computer Networks and Security, chapter 2
- [Radio signal in twisted pair and coaxial cable](https://www.bctengineer.com/question.md?key=semester_8%2Ftelecommunications%3Aradio-signal-twisted-coaxial) — Telecommunications, chapter 2
- [Optical fiber advantages and wireless media](https://www.bctengineer.com/question.md?key=semester_8%2Ftelecommunications%3Aoptical-fiber-wireless-media) — Telecommunications, chapter 2
- [Advantages of optical fiber over copper](https://www.bctengineer.com/question.md?key=semester_5%2Finstrumentation_ii%3Aoptical-fiber-advantages) — Instrumentation II, chapter 5, asked 3×