Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Fibre Optics > Optical Fibre Theory > Flashcards

Optical Fibre Theory Flashcards

1
Q

Define the term “Propagation”?

A

Propagation is a process by which light or sound waves travel.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the two types of Optical Fibre?

A

Single Mode (SM) fibre type

Multi-Mode (MM) fibre type

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Explain why refraction occurs?

A

Refraction occurs because light travels at different speeds in different materials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does NA stand for?

A

Numerical Aperture (NA);

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

By what means does light travel along an Optical Fibre?

A

Stepped Index

Graded Index;

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What the typical sizes of Multimode Optical Fibre?

A
  • 50/125 or 50/125/250
  • 62.5/125 or 62.5/125/250

?80/125 or 80/125/250?
?100/140 or 100/140/280?
?200/240 or 200/240/480?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the typical size for Single Mode Optical Fibre?

A

• 8/125 or 8/125/250

?9/125 or 9/125/250?
?10/125 or 10/125/250?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Outside Vapour Deposition is one method of fibre manufacture, what is the other?

A

Modified Chemical Vapour Deposition (MCVD).

or

Outside Vapour Deposition (OVD)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Multimode is often referred to as OM, what does this stand for?

A

OM = Optical Multimode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the attenuation of 62.5/125 optical fibre cable operating within the First Window of Operation?

A

850nm / 3.5(dB/km)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the attenuation of 50/125 optical fibre cable operating within the Second Window of Operation?

A

1300nm / 1.5(dB/km)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Multimode optical fibre has two different core construction, what are these?

A

Stepped index

Graded index

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Modal Dispersion is associated with which type of Multimode optical fibre?

A

Multimode - Step Index

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What effect does Graded Index optical fibre have on light rays?

A

The effect of Graded Index fibre is to drastically reduce the Modal Dispersion of multimode fibres by slowing down the rays with shorter paths relative to those with longer paths through the fibre.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

State the benefits of Multimode optical fibre?

A
  • Bend Radius/Flexibility

* Cheaper Tx/Rx Equipment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

State the drawbacks of using Multimode optical fibre?

A
  • Lower Bandwidth
  • Expensive Cable
  • Short distance only
17
Q

Single mode is often referred to as OS, what does this stand for?

A

OS = Optical Single Mode

18
Q

What is the difference between OS1 and OS2 optical fibre cables?

A

OS1 is specified for upto 2km (Internal)

OS2 is Specified for over 2km (external)

19
Q

Explain the term “Chromatic Dispersion”?

A

Chromatic dispersion (CD) is caused by the fact that single mode glass fibres transmit light of different wavelengths at different speeds.

20
Q

State the benefits of Single mode optical fibre?

A
  • Longer Distances
  • Higher Bandwidth
  • Cheaper Cable
21
Q

State the drawback of Single mode optical fibre?

A
  • Less bend radius tolerances
  • Finer connector tolerances
  • Expensive Tx/Rx equipment
22
Q

What is the attenuation of OS2 optical fibre cable operating within the Third Window of Operation?

A

1550nm / 0.4(dB/km)

23
Q

What three key parameters which categorise the performance of an Optical Fibre?

A
  • Launch Power
  • Attenuation
  • Bandwidth
24
Q

What unit of measurement is used to denote attention?

A

Decibels (dB)

25
Q

What are the four causes of attenuation in optical fibres?

A
  • Attenuation through absorption
  • Attenuation through scattering
  • Waveguide attenuation through macro bending
  • Waveguide attenuation through micro bending
26
Q

Ty-wraps are not to be used for affixing optical fibre cables as this can cause which type of bend?

A

Micro Bends

27
Q

Define the term “Macro Bending”?

A

These are fibre bends with a radius of curvature of the order of millimetres.

Going over the bend radius

28
Q

Define the term “Bandwidth”?

A

Bandwidth describes the information-carrying capacity of a fibre optic system, usually measured in bits per second (Mb/s or Gb/s)

29
Q

Which type of optical fibre provides the highest bandwidth?

A

8/125 single-mode has a much higher bandwidth.

Fibre Optics (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions