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This section includes 21 Mcqs, each offering curated multiple-choice questions to sharpen your Optical Communication knowledge and support exam preparation. Choose a topic below to get started.
1. |
Considering the values given below, calculate the mode separation in terms of free space wavelength for a laser. (Frequency separation = 2GHz, Wavelength = 0.5 μm) |
A. | 1.4×10-11 |
B. | 1.6×10-12 |
C. | 1×10-12 |
D. | 6×10-11 |
Answer» C. 1×10-12 | |
2. |
An injection laser has active cavity losses of 25 cm-1 and the reflectivity of each laser facet is 30%. Determine the laser gain coefficient for the cavity it has a length of 500μm. |
A. | 46 cm-1 |
B. | 51 cm-1 |
C. | 50 cm-1 |
D. | 49.07 cm-1 |
Answer» E. | |
3. |
A ruby laser has a crystal of length 3 cm with a refractive index of 1.60, wavelength 0.43 μm. Determine the number of longitudinal modes. |
A. | 1×102 |
B. | 3×106 |
C. | 2.9×105 |
D. | 2.2×105 |
Answer» E. | |
4. |
__________________ in the laser occurs when photon colliding with an excited atom causes the stimulated emission of a second photon. |
A. | Light amplification |
B. | Attenuation |
C. | Dispersion |
D. | Population inversion |
Answer» B. Attenuation | |
5. |
An incandescent lamp is operating at a temperature of 1000K at an operating frequency of 5.2×1014 Hz. Calculate the ratio of stimulated emission rate to spontaneous emission rate. |
A. | 3×10-13 |
B. | 1.47×10-11 |
C. | 2×10-12 |
D. | 1.5×10-13 |
Answer» C. 2×10-12 | |
6. |
The frequency of the absorbed or emitted radiation is related to difference in energy E between the higher energy state E2 and the lower energy state E1. State what h stands for in the given equation? |
A. | Gravitation constant |
B. | Planck’s constant |
C. | Permittivity |
D. | Attenuation constantView Answer |
Answer» C. Permittivity | |
7. |
A device which converts electrical energy in the form of a current into optical energy is called as ___________ |
A. | Optical source |
B. | Optical coupler |
C. | Optical isolator |
D. | Circulator |
Answer» B. Optical coupler | |
8. |
A_RUBY_LASER_HAS_A_CRYSTAL_OF_LENGTH_3_CM_WITH_A_REFRACTIVE_INDEX_OF_1.60,_WAVELENGTH_0.43_‚ÂÀ√≠¬¨‚À´M._DETERMINE_THE_NUMBER_OF_LONGITUDINAL_MODES.?$# |
A. | 1√ó10<sup>2 </sup> |
B. | 3√ó10<sup>6 </sup> |
C. | 2.9√ó10<sup>5 </sup> |
D. | 2.2√ó10<sup>5 </sup> |
Answer» E. | |
9. |
Doppler broadening is a homogeneous broadening mechanism. State whether the given statement is true or false.$ |
A. | True |
B. | False |
Answer» C. | |
10. |
A_semiconductor_laser_crystal_of_length_5_cm,_refractive_index_1.8_is_used_as_an_optical_source._Determine_the_frequency_separation_of_the_modes.$ |
A. | 2.8 GHz |
B. | 1.2 GHz |
C. | 1.6 GHz |
D. | 2 GHz |
Answer» D. 2 GHz | |
11. |
Considering the values given below, calculate the mode separation in terms of free space wavelength for a laser. |
A. | |
B. | |
Answer» C. | |
12. |
Longitudinal modes contribute only a single spot of light to the laser output. State whether the given statement is true or false. |
A. | True |
B. | False |
Answer» B. False | |
13. |
An_injection_laser_has_active_cavity_losses_of_25_cm-1and_the_reflectivity_of_each_laser_facet_is_30%._Determine_the_laser_gain_coefficient_for_the_cavity_it_has_a_length_of_500μm.$ |
A. | 46 cm<sup>-1</sup> |
B. | 51 cm<sup>-1</sup> |
C. | 50 cm<sup>-1</sup> |
D. | 49.07 cm<sup>-1</sup> |
Answer» E. | |
14. |
__________________ in the laser occurs when photon colliding with an excited atom causes the stimulated emission of a second photon? |
A. | Light amplification |
B. | Attenuation |
C. | Dispersion |
D. | Population inversion |
Answer» B. Attenuation | |
15. |
The lower energy level contains more atoms than upper level under the conditions of ________________ |
A. | Isothermal packaging |
B. | Population inversion |
C. | Thermal equilibrium |
D. | Pumping |
Answer» D. Pumping | |
16. |
An incandescent lamp is operating at a temperature of 1000K at an operating frequency of 5.2√ó1014 Hz. Calculate the ratio of stimulated emission rate to spontaneous emission rate.$ |
A. | 3√ó10<sup>-13 </sup> |
B. | 1.47√ó10<sup>-11 </sup> |
C. | 2√ó10<sup>-12 </sup> |
D. | 1.5√ó10<sup>-13 </sup> |
Answer» C. 2‚Äö√†√∂‚àö‚â•10<sup>-12 </sup> | |
17. |
Which process gives the laser its special properties as an optical source? |
A. | Dispersion |
B. | Stimulated absorption |
C. | Spontaneous emission |
D. | Stimulated emission |
Answer» E. | |
18. |
The radiation emission process (emission of a proton at frequency) can occur in __________ ways. |
A. | Two |
B. | Three |
C. | Four |
D. | One |
Answer» B. Three | |
19. |
The frequency of the absorbed or emitted radiation is related to difference in energy E between the higher energy state E2 and the lower energy state E1. State what h stands for in the given equation? |
A. | |
B. | Gravitation constant |
C. | Planck’s constant |
Answer» C. Planck‚Äö√Ñ√∂‚àö√ë‚àö¬•s constant | |
20. |
How many types of sources of optical light are available? |
A. | One |
B. | Two |
C. | Three |
D. | Four |
Answer» D. Four | |
21. |
A device which converts electrical energy in the form of a current into optical energy is called as |
A. | Optical source |
B. | Optical coupler |
C. | Optical isolator |
D. | Circulator |
Answer» B. Optical coupler | |