KONGUNADU COLLEGE OF ENGINEERING AND TECHNOLOGY(AUTONOMOUS)
NAMAKKAL-TRICHY MAIN ROAD, THOTTIAM, TRICHY -621 215
DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING
REGULATIONS - 2017
YEAR/SEM: IV/VII
SUBJECT CODE & NAME: EC8751-OPTICAL COMMUNICATION
QUESTION BANK
UNIT-I
INTRODUCTION TO OPTICAL FIBERS
PART-A
1. Define attenuation constant of a fiber.
2. Define numerical aperture of a step index fiber
3. Define critical angle
4. What is total internal reflection in a fiber?
5. State Snell’s law
6. What is a linearly polarized mode?
7. State the necessity of cladding for an optical fiber.
8. Relate the mode‐field diameter and spot size
9. Outline any four advantages of an optical communication system
10. What is meant by Conical Half angle?
Relate a formula for the normalized frequency and NA. Hence, find the Numerical
11. aperture for a step index fiber that has normalized frequency V=26.6 at a 1300nm
wavelength and core radius of 25µm.
Apply the ray transmission theory to find the critical incident angle for a glass rod of
12.
refractive index 1.5, surrounded by air.
With the knowledge of the total internal reflection, calculate the critical angle of incidence
13.
between two substances with different refractive indices where n1 = 1.5 and n2 = 1.46.
14. Sort out the fundamental parameter of a single mode fiber
15. List out the advantages of the multimode fiber.
16. Distinguish Step index fibers and graded index fiber
Evaluate the critical angle with the relative refractive index difference of 1% for an optical
17.
fiber. Given the core refractive index
Determine the cutoff wavelength of a single mode fiber with core radius of 4µm and ∆ =
18. 0.003.
The refractive indexes of the core and cladding of a silica fiber are 1.48 and 1.46
respectively. Find the acceptance angle for the fiber. Propose a suggestion to increase the
19.
acceptance angle of optical fiber.
Formulate the normalized frequency at 820 nm for a step index fiber having a 25µm
radius. The refractive indexes of the cladding and the core are 1.45 and 1.47 respectively.
20.
Solve to find the number of modes that propagate in this fiber at 820 nm?
PART-B
State how mode‐field diameter is related to the single mode fiber.
21
What are the propagation modes in them?
Draw a neat diagram and explain the ray theory behind the
22 optical fiber communication with a special mention about the total
internal reflection, Acceptance angle and Numerical aperture. (8)
23 Write a note on step index fiber (6)
Page 1
, KONGUNADU COLLEGE OF ENGINEERING AND TECHNOLOGY(AUTONOMOUS)
NAMAKKAL-TRICHY MAIN ROAD, THOTTIAM, TRICHY -621 215
DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING
24 What is numerical aperture of an optical fiber? Deduce an expression for the same. (10)
25 Define normalized frequency for an optical fiber and explain its use(8)
Draw the block diagram of a optical fiber link transmission and explain the different
26
components (8)
Draw and explain the refractive index profile and ray transmission in multimode step index
27
& single mode step index fibers. (8)
28 Explain about transmission of light through graded index fiber with neat diagrams.
Show that linearly polarized modes in optical fibers is related to the V number by obtaining
29
proper equations and expressions. (8)
Show that numerical aperture is dependent on the refractiveindices of core and cladding
30
through proper derivation. (10)
31 Explain the advantages of optical communication technology (6)
UNIT-II
TRANSMISSION CHARACTERISTIC OF OPTICAL FIBER
PART-A
1 What is Mode Coupling?
2 Define dispersion flattening.
3 What is meant by Stimulated Raman Scattering?
4 State signal attenuation.
5 What are bending losses? Name its types.
6 Outline the most important nonlinear effects of optical fiber communication.
7 Discuss the significance of group velocity.
8 Give the measure of information capacity in optical wave guide
9 Classify the fiber losses which are given per unit distance.
Construct an expression for the effective number of modes guided by a curved multimode
10
fiber of radius 'a'.
11 Identify the cause of scattering loss.
12 State the impact of Rayleigh scattering.
13 Inspect the effects of dispersion in multimode fibers.
14 Compare material and waveguide dispersion.
15 List the factors that cause intrinsic joint losses in a fiber.
16 Express group delay in optical fiber.
A fiber has an attenuation of 0.5 dB/Km at 1500 nm. If 0.5mW of optical power is initially
17
launched into the fiber, estimate is the power level in after 25km?
18 What could be done to minimize the pulse broadening?
19 A continuous 12 Kms long optical fiber link has a loss of 1.5dB/Km.
Propose a proper solution to find the minimum optical power that must be launched into
20
the fiber to maintain the optical power level of 0.3 μwatt at the receiving end?
PART-B
What do you mean by pulse broadening? Explain its effect on information carrying capacity
1.
of a fiber. (10)
2. What are the loss or signal attenuation mechanisms in a fiber. Explain (6)
3. What is meant by critical bending radius of optical fibers? Explain
Define signal distortion? How does Signal distortion in single
4.
mode fibers?
5. Describe the linear scattering losses in optical fibers. (8)
Page 2
NAMAKKAL-TRICHY MAIN ROAD, THOTTIAM, TRICHY -621 215
DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING
REGULATIONS - 2017
YEAR/SEM: IV/VII
SUBJECT CODE & NAME: EC8751-OPTICAL COMMUNICATION
QUESTION BANK
UNIT-I
INTRODUCTION TO OPTICAL FIBERS
PART-A
1. Define attenuation constant of a fiber.
2. Define numerical aperture of a step index fiber
3. Define critical angle
4. What is total internal reflection in a fiber?
5. State Snell’s law
6. What is a linearly polarized mode?
7. State the necessity of cladding for an optical fiber.
8. Relate the mode‐field diameter and spot size
9. Outline any four advantages of an optical communication system
10. What is meant by Conical Half angle?
Relate a formula for the normalized frequency and NA. Hence, find the Numerical
11. aperture for a step index fiber that has normalized frequency V=26.6 at a 1300nm
wavelength and core radius of 25µm.
Apply the ray transmission theory to find the critical incident angle for a glass rod of
12.
refractive index 1.5, surrounded by air.
With the knowledge of the total internal reflection, calculate the critical angle of incidence
13.
between two substances with different refractive indices where n1 = 1.5 and n2 = 1.46.
14. Sort out the fundamental parameter of a single mode fiber
15. List out the advantages of the multimode fiber.
16. Distinguish Step index fibers and graded index fiber
Evaluate the critical angle with the relative refractive index difference of 1% for an optical
17.
fiber. Given the core refractive index
Determine the cutoff wavelength of a single mode fiber with core radius of 4µm and ∆ =
18. 0.003.
The refractive indexes of the core and cladding of a silica fiber are 1.48 and 1.46
respectively. Find the acceptance angle for the fiber. Propose a suggestion to increase the
19.
acceptance angle of optical fiber.
Formulate the normalized frequency at 820 nm for a step index fiber having a 25µm
radius. The refractive indexes of the cladding and the core are 1.45 and 1.47 respectively.
20.
Solve to find the number of modes that propagate in this fiber at 820 nm?
PART-B
State how mode‐field diameter is related to the single mode fiber.
21
What are the propagation modes in them?
Draw a neat diagram and explain the ray theory behind the
22 optical fiber communication with a special mention about the total
internal reflection, Acceptance angle and Numerical aperture. (8)
23 Write a note on step index fiber (6)
Page 1
, KONGUNADU COLLEGE OF ENGINEERING AND TECHNOLOGY(AUTONOMOUS)
NAMAKKAL-TRICHY MAIN ROAD, THOTTIAM, TRICHY -621 215
DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING
24 What is numerical aperture of an optical fiber? Deduce an expression for the same. (10)
25 Define normalized frequency for an optical fiber and explain its use(8)
Draw the block diagram of a optical fiber link transmission and explain the different
26
components (8)
Draw and explain the refractive index profile and ray transmission in multimode step index
27
& single mode step index fibers. (8)
28 Explain about transmission of light through graded index fiber with neat diagrams.
Show that linearly polarized modes in optical fibers is related to the V number by obtaining
29
proper equations and expressions. (8)
Show that numerical aperture is dependent on the refractiveindices of core and cladding
30
through proper derivation. (10)
31 Explain the advantages of optical communication technology (6)
UNIT-II
TRANSMISSION CHARACTERISTIC OF OPTICAL FIBER
PART-A
1 What is Mode Coupling?
2 Define dispersion flattening.
3 What is meant by Stimulated Raman Scattering?
4 State signal attenuation.
5 What are bending losses? Name its types.
6 Outline the most important nonlinear effects of optical fiber communication.
7 Discuss the significance of group velocity.
8 Give the measure of information capacity in optical wave guide
9 Classify the fiber losses which are given per unit distance.
Construct an expression for the effective number of modes guided by a curved multimode
10
fiber of radius 'a'.
11 Identify the cause of scattering loss.
12 State the impact of Rayleigh scattering.
13 Inspect the effects of dispersion in multimode fibers.
14 Compare material and waveguide dispersion.
15 List the factors that cause intrinsic joint losses in a fiber.
16 Express group delay in optical fiber.
A fiber has an attenuation of 0.5 dB/Km at 1500 nm. If 0.5mW of optical power is initially
17
launched into the fiber, estimate is the power level in after 25km?
18 What could be done to minimize the pulse broadening?
19 A continuous 12 Kms long optical fiber link has a loss of 1.5dB/Km.
Propose a proper solution to find the minimum optical power that must be launched into
20
the fiber to maintain the optical power level of 0.3 μwatt at the receiving end?
PART-B
What do you mean by pulse broadening? Explain its effect on information carrying capacity
1.
of a fiber. (10)
2. What are the loss or signal attenuation mechanisms in a fiber. Explain (6)
3. What is meant by critical bending radius of optical fibers? Explain
Define signal distortion? How does Signal distortion in single
4.
mode fibers?
5. Describe the linear scattering losses in optical fibers. (8)
Page 2
