In one line
Optical fibres carry far more information over longer distances with lower loss and no electrical interference, while being lighter, safer and more secure than copper cables.
Explained simply
Copper wires carry electrons; fibres carry light. Light has a much higher frequency, so it can carry far more data, and since glass does not conduct electricity, lightning, motors and nearby cables do not disturb it.
How it works
- Huge bandwidth: light frequencies are around \(10^{14}\) Hz, so very high data rates are possible.
- Low attenuation: about 0.2 dB/km at 1550 nm, so repeaters can be spaced far apart.
- Immune to electromagnetic interference: glass is an insulator, so nearby power lines and motors do not induce noise.
- No crosstalk: light stays inside each fibre, so signals in neighbouring fibres do not mix.
- Security: it is very hard to tap a fibre without detection because light does not radiate out.
- Small size and light weight: a fibre is about as thin as a hair; cables are easier to install.
- Electrical isolation and safety: no sparks or short circuits, so they are safe in explosive or high-voltage areas.
- Cheap raw material: silica (sand) is abundant, unlike copper.
Limitations (good to mention): splicing and connecting need skill and special tools, fibres can break if bent sharply, and transmitters/receivers cost more.
Quick example
Bank ATMs, hospital equipment near MRI machines and railway signalling use fibre links because electromagnetic interference would corrupt signals on copper. Internet backbones between cities are almost entirely fibre.
Common mistakes
- Saying fibres have "no loss at all"; loss is low, not zero.
- Listing only bandwidth and missing EMI immunity and security.
- Claiming fibres carry electricity; they carry light only.
How MU asks it
Asked as "State advantages of optical fibre communication" (3 marks) or "Compare fibre with copper communication" (5 marks). List at least six points with a one-line reason each; a table comparing fibre and copper scores well.