Explore topic-wise MCQs in Optical Communications.

This section includes 11 Mcqs, each offering curated multiple-choice questions to sharpen your Optical Communications knowledge and support exam preparation. Choose a topic below to get started.

1.

Digital transmission is more likely to be affected by modal noise.

A. True
B. False
Answer» C.
2.

The modal noise can be reduced by __________

A. Decreasing width of signal longitudinal mode
B. Increasing coherence time
C. Decreasing number of longitudinal modes
D. Using fiber with large numerical aperture
Answer» E.
3.

Disturbance along the fiber such as vibrations, discontinuities, connectors, splices, source/detectors coupling result in __________

A. Modal noise
B. Inter-symbol interference
C. Infrared interference
D. Pulse broadening
Answer» B. Inter-symbol interference
4.

The modal noise occurs when uncorrected source frequency is?

A. f>>1/ T
B. f=1/ T
C. f<<1/ T
D. Negligible
Answer» B. f=1/ T
5.

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

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/km
Answer» C. 0.23 to 5 ns/km
6.

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

A. True
B. False
Answer» C.
7.

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

A. N (r) = n1 [1 2 (r<sup>2</sup>/a)<sup>2</sup>]<sup>1/2</sup>; r&lt;a
B. N (r) = n1 [3 2 (r<sup>2</sup>/a)<sup>2</sup>]<sup>1/2</sup>; r&lt;a
C. N (r) = n1 [5 2 (r<sup>2</sup>/a)<sup>2</sup>]<sup>1/2</sup>; r&gt;a
D. N (r) = n1 [1 2 (r<sup>2</sup>/a)<sup>2</sup>]<sup>1/2</sup>; r&lt;a
Answer» E.
8.

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

A. True
B. False
Answer» B. False
9.

Consider a single mode fiber having core refractive index n1= 1.5. The fiber length is 12m. Find the time taken by the axial ray to travel along the fiber.

A. 1.00 sec
B. 0.06 sec
C. 0.90 sec
D. 0.30 sec
Answer» C. 0.90 sec
10.

After Total Internal Reflection the Meridional ray __________

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 ray
Answer» E.
11.

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

A. Propagation of the fiber
B. Propagating through the fiber
C. Pulse broadening at output
D. Attenuation of waves
Answer» D. Attenuation of waves