Fibre Optics

Question 1

Gives 3 uses of optic fibers?

Answer 1

Light guides for laser surgery

Missile launches

electric trains

Question 2

3 advantages of Fibre optics?

Answer 2

greater bandwidth

Can be submerged in water

Not temperature dependent

Question 3

Basic function of the Fibre optic cable?

Answer 3

1. Converts electrical signal to optical signal
2. Send optical signal along optical Fibre
3. Convert optical signal back into electrical signal

Question 4

3 main parts of the optic Fibre cable?

Answer 4

Transmitter: Converts input signal into an optical signal

Optical Fibre: Transmitted signal will get weakened and distorted due to scattering

receiver: Converts the optical signal back into the electrical signal

Question 5

3 ways that Fibre optics experience signal loss (attenuation)

Answer 5

Absorption loss (absorbing impurities)

Scattering loss (photonic interaction with glass)

Bending loss (physical stress on Fibre)

Question 6

What are the two types of absorption loss?

Answer 6

Intrinsic: Interaction of two or more components of the glass

Extrinsic: Caused by impurities within the glass

Question 7

What are the 3 types of dispersion?

Answer 7

Modal: Caused in MM fibres as different modes travel at different speeds

Chromatic: Light is made of different wavelengths that travel at different speeds

Polarisation: Only occurs in SM fibres

Question 8

Single mode vs Multimode optic fibres?

Answer 8

Single mode: Only one strand of Fibre with a single path. Lower attenuation and further travel

Multimode: Light can travel in multiple modes, larger Fibre diameter than single mode. Higher attenuation, short travel

Question 9

What is the equation for Rayleigh loss?

Answer 9

Rayleigh loss = Rayleigh scattering coefficient / (wavelength^4)