Year 12s: what will be the first way you research your future options? >>

P4 ques

Huzaifa-981

Why infra-red radiation rather than visible light usually used in optic fibres?

Reply 1

uberteknik

Original post by Huzaifa-981

Why infra-red radiation rather than visible light usually used in optic fibres?

Hello and welcome to TSR physics. :smile:

It's because infra red has a longer wavelength than visible light and is not attenuated (scattered and absorbed) as much by the glass fibres at these wavelengths, thus preserving the signal to noise ratio over longer distances.

The transmitted signal can therefore travel much further without needing a repeater station (amplifier) to both clean up and boost the signal at regularly spaced intervals. This reduces the cost of long distance installations, operation and maintenance considerably.