Question 1

How many categories of nonlinear effects are seen in optical fibers?

Accepted Answer

A)  one
B)  two
C)  three
D)  fourE) A) and B)
F) A) and C) B

Question 2

Intermodal dispersion occurring in a large amount in multimode step index fiber results in

Accepted Answer

A)   propagation of the fiber
B)  propagating through the fiber
C)  pulse broadening at output
D)  attenuation of wavesE) B) and C)
F) C) and D)

Question 3

3dB optical bandwidth is always ___________ the 3dB electrical bandwidth.

Accepted Answer

A)  smaller than
B)  larger than
C)  negligible than
D)  equal toE) C) and D)
F) B) and D) B

Question 4

The optical source used in a fiber is an injection laser with a relative spectral width ??/? of 0.0011 at a wavelength of 0.70?m. Estimate the RMS spectral width.

Accepted Answer

A)  1.2 nm
B)  1.3 nm
C)  0.77 nm
D)  0.98 nmE) B) and C)
F) A) and D)

Question 5

A 4 km optical link consists of multimode step index fiber with core refractive index of 1.3 and a relative refractive index difference of 1%. Find the delay difference between the slowest and fastest modes at the fiber output.

Accepted Answer

A)  0.173 ?sec
B)  0.152 ?sec
C)  0.96 ?sec
D)  0.121 ?secE) C) and D)
F) B) and C)

Question 6

A multimode graded index fiber exhibits a total pulse broadening of 0.15?sover a distance of 16 km. Estimate the maximum possible bandwidth, assuming no intersymbol interference.

Accepted Answer

A)  4.6 mhz
B)  3.9 mhz
C)  3.3 mhz
D)  4.2 mhzE) A) and B)
F) A) and C)

Question 7

In waveguide dispersion, refractive index is independent of

Accepted Answer

A)  bit rate
B)  index difference
C)  velocity of medium
D)  wavelengthE) C) and D)
F) None of the above

Question 8

Which of the following is not related to Kerr effects?

Accepted Answer

A)  self-phase modulation
B)  cross-phase modulation
C)  four-wave mixing
D)  stimulated raman scatteringE) A) and D)
F) A) and C)

Question 9

What is pulse dispersion per unit length if for a graded index fiber, 0.1?s pulse broadening is seen over a distance of 13 km?

Accepted Answer

A)  6.12ns/km
B)  7.69ns/km
C)  10.29ns/km
D)  8.23ns/kmE) None of the above
F) All of the above

Question 10

Intermodal dispersion in multimode fibers is minimized with the use of step-index fibers.

Accepted Answer

A) True 
 B)False

Question 11

Linear scattering effects are _______ in nature.

Accepted Answer

A)  elastic
B)  non-elastic
C)  mechanical
D)  electricalE) A) and C)
F) A) and B)

Question 12

Self-phase modulation causes modifications to the pulse spectrum.

Accepted Answer

A) True 
 B)False

Question 13

Practical pulse broadening value for graded index fiber lies in the range of

Accepted Answer

A)  0.9 to 1.2 ns/km
B)  0.2 to 1 ns/km
C)  0.23 to 5 ns/km
D)  0.45 to 8 ns/kmE) B) and D)
F) A) and D)

Question 14

Chromatic dispersion is also called as intermodal dispersion. State whether the given statement true or false.

Accepted Answer

A) True 
 B)False

Question 15

The differential attenuation of modes reduces intermodal pulse broadening on a multimode optical link.

Accepted Answer

A) True 
 B)False

Question 16

After Total Internal Reflection the Meridional ray

Accepted Answer

A)  makes an angle equal to acceptance angle with the axial ray
B)  makes an angle equal to critical angle with the axial ray.
C)  travels parallel equal to critical angle with the axial ray
D)  makes an angle equal to critical angle with the axial rayE) A) and D)
F) B) and D)

Question 17

_________ semiconductor laser sources generally have broader bandwidths.

Accepted Answer

A)  injection
B)  pulsed
C)  solid-state
D)  silicon hybridE) A) and B)
F) A) and C)

Question 18

The index profile of a core of multimode graded index fiber is given by-

Accepted Answer

A)  n (r)  = n1 [1 - 2?(r2/a) 2]1/2; r
B)  n (r)  = n1 [3 - 2?(r2/a) 2]1/2; r
C)  n (r)  = n1 [5 - 2?(r2/a) 2]1/2; r>a
D)  n (r)  = n1 [1 - 2?(r2/a) 2]1/2; r<a.E) A) and D)
F) A) and C)

Question 19

Consider a single mode fiber having core refractive index n1= 1.5.

Accepted Answer

A)  1.00?sec
B)  0.06?sec
C)  0.90?sec
D)  0.30?secE) A) and D)
F) A) and C) B

Question 20

Nonlinear effects which are defined by the intensity - dependent refractive index of the fiber are called as

Accepted Answer

A)  scattering effects
B)  kerr effects
C)  raman effects
D)  tomlinson effectsE) None of the above
F) A) and D)

Exam 5: Fiber Optics and Dispersion

How many categories of nonlinear effects are seen in optical fibers?

Correct AnswerverifiedB

Intermodal dispersion occurring in a large amount in multimode step index fiber results in

Correct AnswerverifiedShow Answer

3dB optical bandwidth is always ___________ the 3dB electrical bandwidth.

Correct AnswerverifiedB

The optical source used in a fiber is an injection laser with a relative spectral width ??/? of 0.0011 at a wavelength of 0.70?m. Estimate the RMS spectral width.

Correct AnswerverifiedShow Answer

A 4 km optical link consists of multimode step index fiber with core refractive index of 1.3 and a relative refractive index difference of 1%. Find the delay difference between the slowest and fastest modes at the fiber output.

Correct AnswerverifiedShow Answer

A multimode graded index fiber exhibits a total pulse broadening of 0.15?sover a distance of 16 km. Estimate the maximum possible bandwidth, assuming no intersymbol interference.

Correct AnswerverifiedShow Answer

In waveguide dispersion, refractive index is independent of

Correct AnswerverifiedShow Answer

Which of the following is not related to Kerr effects?

Correct AnswerverifiedShow Answer

What is pulse dispersion per unit length if for a graded index fiber, 0.1?s pulse broadening is seen over a distance of 13 km?

Correct AnswerverifiedShow Answer

Intermodal dispersion in multimode fibers is minimized with the use of step-index fibers.

Correct AnswerverifiedShow Answer

Linear scattering effects are _______ in nature.

Correct AnswerverifiedShow Answer

Self-phase modulation causes modifications to the pulse spectrum.

Correct AnswerverifiedShow Answer

Practical pulse broadening value for graded index fiber lies in the range of

Correct AnswerverifiedShow Answer

Chromatic dispersion is also called as intermodal dispersion. State whether the given statement true or false.

Correct AnswerverifiedShow Answer

The differential attenuation of modes reduces intermodal pulse broadening on a multimode optical link.

Correct AnswerverifiedShow Answer

After Total Internal Reflection the Meridional ray

Correct AnswerverifiedShow Answer

_________ semiconductor laser sources generally have broader bandwidths.

Correct AnswerverifiedShow Answer

The index profile of a core of multimode graded index fiber is given by-

Correct AnswerverifiedShow Answer

Consider a single mode fiber having core refractive index n1= 1.5.

Correct AnswerverifiedB

Nonlinear effects which are defined by the intensity - dependent refractive index of the fiber are called as

Correct AnswerverifiedShow Answer

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B

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B

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B

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