1. Doppler broadening is a homogeneous broadening mechanism.
Correct : B. false
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.
Correct : D. 49.07 cm-1
3. Longitudinal modes contribute only a single spot of light to the laser output.
Correct : A. true
4. 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)
Correct : B. 1.6×10-12
5. is essentially a crude form of Amplitude shift keying.
Correct : B. digital intensity modulation
6. Almost of the transmitter power is wasted in the use of external modulators.
Correct : A. half
7. The line width in the range of bit rate is specified for ASK heterodyne detection.
Correct : C. 10 t0 50%
8. does not require an external modulator.
Correct : A. fsk
9. The frequency deviation at frequencies above 1 MHz is typically
Correct : B. 100 to 500 ma-1
10. offers the potential for improving the coherent optical receiver sensitivity by increasing the choice of signalling frequencies.
Correct : A. mfsk
11. Eight level FSK and binary PSK yields an equivalent sensitivity.
Correct : B. true
12. External modulation for modulation format allows the most sensitive coherent detection mechanism.
Correct : C. psk
13. can potentially provide spectral conservation through the use of multilevel signalling.
Correct : A. m-ary psk
14. The digital transmission on implementation of polarization modulation which involves polarization characteristics of the transmitted optical signal is known as
Correct : D. polarization shift keying
15. is fully depleted by employing electric fields.
Correct : A. avalanche photodiode
16. At low gain, the transit time and RC effects
Correct : C. dominate
17. The phenomenon leading to avalanche breakdown in reverse-biased diodes is known as
Correct : D. dominates
18. Often pulse shape is obtained from APD.
Correct : C. asymmetric
19. Fall times of 1 ns or more are common.
Correct : B. true
20. Determine Responsivity of a silicon RAPD with 80% efficiency, 0.7μm wavelength.
Correct : A. 0.459
21. Compute wavelength of RAPD with 70% efficiency and Responsivity of 0.689 A/w.
Correct : C. 0.112μm
22. 49 A/w.
Correct : D. 0.80 μw
23. Determine the Responsivity of optical power of 0.4μW and photocurrent of 0.294 μA.
Correct : A. 0.735
24. Compute multiplication factor of RAPD with output current of 10 μAand photocurrent of 0.369μA.
Correct : B. 27.100
25. Determine the output current of RAPD having multiplication factor of 39 and photocurrent of 0.469μA.
Correct : D. 18.29
26. Compute the photocurrent of RAPD having multiplication factor of 36.7 and output current of 7μA.
Correct : A. 0.01 μa
27. How many circuits are present in an equivalent circuit for the digital optical fiber receiver?
Correct : A. four
28. compensates for distortion of the signal due to the combined transmitter, medium and receiver characteristics.
Correct : C. equalization
29. The phase frequency response of the system should be in order to minimize inter-symbol interference.
Correct : B. linear
30. Noise contributions from the sources should be minimized to maximize the receiver sensitivity.
Correct : A. true
31. How many amplifier configurations are frequently used in optional fiber communication receivers?
Correct : C. three
32. How many receiver structures are used to obtain better receiver characteristics?
Correct : D. three
33. The high-impedance front-end amplifier provides a far greater bandwidth than the trans-impedance front-end.
Correct : A. true
34. A high-impedance amplifier has an effective input resistance of 4MΩ. Find the maximum bandwidth that may be obtained without equalization if the total capacitance is 6 pF and total effective load resistance is 2MΩ.
Correct : A. 13.3 khz
35. The major advantage of the trans- impedance configuration over the high- impedance front end is
Correct : C. greater dynamic range
36. The trans-impedance front end configuration operates as a with negative feedback.
Correct : A. current mode amplifier
37. is also known as frequency- shaping filter.
Correct : D. equalizer
38. affects both the fiber attenuation and dispersion.
Correct : B. micro-bending
39. Which of the following is not included in the optical fiber link measurement test?
Correct : D. receiver sensitivity
40. In case of field measurements, the equipment must have power consumption keeping in mind the battery operation.
Correct : A. low
41. Which of the following are not considered as environmental conditions required for field measurements?
Correct : D. power
42. Which of the following cannot be used in equipment for field measurements?
Correct : C. external triggering
43. Which sensors are used for alteration of spectral range in equipment?
Correct : A. wide-area photodiodes
44. The handheld optical power meter has a measurement accuracy of
Correct : B. 0.25 db
45. may be used for measurement of the absolute optical attenuation on a fiber link.
Correct : C. optical power meters
46. A large-area photodiode is utilized in the receiver to eliminate any effects from differing fiber and faces.
Correct : A. true
47. Optical time domain reflectometry is also called a backscatter measurement method.
Correct : B. true
48. When considering source-to-fiber coupling efficiencies, the is an important parameter than total output power.
Correct : B. radiance of an optical source
49. It is a device that distributes light from a main fiber into one or more branch fibers.
Correct : A. optical fiber coupler
50. Optical fiber couplers are also called as
Correct : C. directional couplers
51. How many types of multiport optical fiber couplers are available at present?
Correct : D. three
52. The optical power coupled from one fiber to another is limited by
Correct : D. number of modes propagating in each fiber
53. couplers combine the different wavelength optical signal onto the fiber or separate the different wavelength optical signal output from the fiber.
Correct : C. wdm
54. How many fabrication techniques are used for 3 port fiber couplers?
Correct : B. two
55. Which is the most common method for manufacturing couplers?
Correct : D. fused bi-conical taper (fbt) technique
56. Couplers insertion loss is same as that of excess loss.
Correct : B. false
57. The measured output power at ports 2,3 and 4 are 0.003, 23.0 and 24.5 μW respectively. Determine the excess loss.
Correct : A. 0.22 db
58. How many manufacturing methods are used for producing multimode fiber star couplers?
Correct : A. two
59. Calculate the splitting loss if a 30×30 port multimode fiber star coupler has 1 mW of optical power launched into an input port.
Correct : C. 14.77 db
60. A coupler comprises a number of cascaded stages, each incorporating three or four-port FBT couplers to obtain a multiport output.
Correct : A. star
61. 2 dB along with a splice loss of 0.1 dB at the interconnection of each stage. Determine the excess loss.
Correct : D. 1.1 db
62. A permanent joint formed between two different optical fibers in the field is known as a
Correct : A. fiber splice
63. The insertion losses of the fiber splices are much less than the Fresnel reflection loss at a butted fiber joint.
Correct : A. true
64. What is the main requirement with the fibers that are intended for splicing?
Correct : B. smooth and square end faces
65. In score and break process, which of the following is not used as a cutting tool?
Correct : D. copper
66. The heating of the two prepared fiber ends to their fusing point with the application of required axial pressure between the two optical fibers is called as
Correct : B. fusion splicing
67. Which of the following is not used as a flame heating source in fusion splicing?
Correct : D. gas burner
68. The rounding of the fiber ends with a low energy discharge before pressing the fibers together and fusing with a stronger arc is called as
Correct : A. pre-fusion
69. is caused by surface tension effects between the two fiber ends during fusing.
Correct : C. self-alignment
70. Mean splice insertion losses of 0.05 dB are obtained using multimode graded index fibers with the Springroove splice.
Correct : A. true
71. is the unique property of the glass fiber.
Correct : A. transmission
72. limits the maximum distance between the optical fiber transmitter and receiver.
Correct : A. attenuation
73. The incorporates a line receiver in order to convert the optical signal into the electrical regime.
Correct : C. repeater
74. A regenerative repeater is called as
Correct : B. regenerator
75. How many encoding schemes are used in optical fiber communication system design requirements?
Correct : C. two
76. In the optical channel bandwidth is divided into non-overlapping frequency bands.
Correct : B. frequency division multiplexing
77. A multiplexing technique which does not involve the application of several message signals onto a single fiber is called as
Correct : D. space division multiplexing
78. Which of the following is not an optical fiber component?
Correct : C. circulator
79. technique involves an increase in the number of components required.
Correct : B. space division multiplexing
80. Time division multiplexing is inverse to that of frequency division multiplexing.
Correct : A. true
81. SONET stands for
Correct : A. synchronous optical network
82. In SONET, STS-1 level of electrical signalling has the data rate of
Correct : A. 51.84 mbps
83. The path layer of SONET is responsible for the movement of a signal
Correct : B. across a physical line
84. The photonic layer of the SONET is similar to the of OSI model.
Correct : C. physical layer
85. In SONET, each synchronous transfer signal STS-n is composed of
Correct : C. 8000 frames
86. Which one of the following is not true about SONET?
Correct : D. sts-1 provides the data rate of 622.080mbps
87. A linear SONET network can be
Correct : C. both point-to-point and multi-point
88. Automatic protection switching in linear network is defined at the
Correct : A. line layer
89. A unidirectional path switching ring is a network with
Correct : B. two rings
90. is a multi-functional element of optical network.
Correct : B. optical node
91. A signal carried on a dedicated wavelength from source to destination node is known as a
Correct : A. light path
92. The fundamentals of optical networking are divided into areas.
Correct : D. three
93. The network structure formed due to the interconnectivity patterns is known as a
Correct : C. topology
94. In the topology, the data generally circulates bi-directionally.
Correct : B. bus
95. The ring and star topologies are combined in a configuration.
Correct : A. mesh
96. The full-mesh configuration is complex.
Correct : B. true
97. How many networking modes are available to establish a transmission path?
Correct : C. two
98. Packet switching is also called as
Correct : B. cell switching
99. mode is temporary, selective and continuous.
Correct : D. circuit switching
100. A is a series of logical connections between the source and destination nodes.