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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<a |
B. | N (r) = n1 [3 2 (r<sup>2</sup>/a)<sup>2</sup>]<sup>1/2</sup>; r<a |
C. | N (r) = n1 [5 2 (r<sup>2</sup>/a)<sup>2</sup>]<sup>1/2</sup>; r>a |
D. | N (r) = n1 [1 2 (r<sup>2</sup>/a)<sup>2</sup>]<sup>1/2</sup>; r<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 | |