Fibre Optics
- Fibre optics utilise the phenomenon of total internal reflection to send high speed light signals over large distances
- These have many important uses, including:
- Communications, such as telephone and internet transmission
- Medical imaging, such as endoscopes
A light ray is totally internally reflected down an optical fibre
- There are three main components that make up optical fibres:
- An optically dense core, such as plastic or glass
- A lower optical density cladding surrounding the core
- An outer sheath
- Since the refractive index of the core is more than the refractive index of the cladding, this allows TIR to occur
- ncladding < ncore
- The outer sheath:
- Prevents physical damage to the fibre
- Strengthens the fibre
- Protects the fibre from the outside from scratches
- The cladding is also required because:
- It protects the core from damage
- It prevents signal degradation through light escaping the core, which can cause information from the signal to be lost
- It keeps signals secure and maintains the quality of the original signal
- It prevents scratching of the core
- It keeps the core away from adjacent fibre cores hence preventing crossover of information to other fibres
- It provides the fibre with strength and prevents breakage given that the core needs to be very thin