Fibre Optics Flashcards
What happens in fibre optics
light continually TIR and transmits signal
What do regenerators do in fibre optics
read
regnerate
resend
What happens to light if material is not transparent
some light absorbed and signal is attenuated and lost
What is pulse broadening
light is ‘smeared out’ due to rays taking different travel times
What are the two causes for pulse broadening
material dispersion
modal dispersion
What is material dispersion
light consists of diff wavelengths so travel at different speeds through medium
What is modal dispersion
light enters at different angles so take different paths
How can modal dispersion be reduced
thin core
make cladding (n1) only slightly more refractive index
How can material dispersion be reduced
use monochromatic light
What are the purposes of cladding
prevent core scratched
strengthening
prevent cross-over
What type of fibre optics do we look at
step index fibre
