FO Losses

Question 1

What is Attenuation?

Answer 1

Reduction of optical signal as it propogates along the fibre. Expressed in dB/Km

Question 2

What factors affect attenuation?

Answer 2

Quality of raw material
Quality of manufacturing process
The wavelength of operation
Refraction index
bending

Question 3

2 types of bending?

Answer 3

Micro bending

Macro bending

Question 4

2 types of absorption in FO?

Answer 4

Intrinsic - intercation with one or more components of glass

Extrinsic - Impurities within the glass

Question 5

Briefly explain Material absorption (Extrinsic)?

Answer 5

Power loss machanism due to molecular resonance and impurities wich convert optical power into heat and therefore loss optical power

Question 6

Name 2 types of scattering?

Answer 6

Rayleight scattering (most common)
MIE scattering
Backscatter
Fresnell Loss (up to 4%)

Question 7

What is normally found at fusion splices?

Answer 7

Mode coupling

Question 8

To Prevent ______ propagating along the fibre we can employ ______ By inserting a ______ fitted to the cable

Answer 8

Leaky modes
Mode stripping
Mandrel

Question 9

4 types of dispersion?

Answer 9

Modal Dispersion
Waveguide Dispersion
Material Dispersion
Chromatic Dispersion

Question 10

what is the zero dispersion point?

Answer 10

1310nm