Question 4
(a) Explain the principle of transmitting signals in fibre optics.
(b) State one advantage of optical fibre over copper cables
Observation
Few candidates who attempted this question performed averagely. Most candidtates were ignorant of how signals are transmitted in optical fibre and also were unable to state the advantages of optical fibre over copper cables.
The expected answers
(a) Explanation of the principle of transmitting signals in Fibre Optics
Light rays entering the fibre optics suffers total internal reflection at the core-cladding interface. Due to the nature/make of the interface the process of total internal reflection continues down the length of the tube .
(b) Advantage of optical fibre over copper cables: It
- transmits signals faster
- is not affected by external electromagnetic signals
- is cheaper / easier to maintain
- transmits signals over longer distance
- has greater bandwidth
- has higher reliability