1. Fibre optics
TIR
Uses –endoscopes
- communications

2. Lower refractive index cladding
Highly transparent glass
Use of cladding
-minimises absorption
-crossover avoided, secure signal
Rays in the fibre which reach the cladding boundary with low angles of incidence will
not undergo TIR
The cladding ensures that all rays in the signal have a large angle of incidence and
hence they will be less likely to be lost from the fibre
This makes it less likely that light gets into an adjacent fibre (crossover)

3. If all rays travel along the axis of the fibre the pulse (information)
arrives at the other end of the fibre with no distortion of the signal.

4. rays travelling along different paths travel different distances along the core
this causes the received pulse to become longer and means that success pulses
of information may merge together
this effect is known as multi-path distortion
narrow diameter fibres are used as the core to minimise this effect

5. Spectral dispersion of white light
is when the signal is split up (spread out)
Monochromatic light (IR radiation) used
to avoid this problem