Upwork Test Answers: Get all the correct answers of most recent and possible Upwork Tests A to Z (Updated on Jan, 2016)
Cover Letter Templates: These cover letter samples are not only for Upwork job, but also you will have some idea about your real life job
Freelance Profile Overviews: Different Profile samples and overviews of experts, advanced and intermediate level freelancers
For Newbie of Upwork: Upwork Help - How to apply for a job in Upwork with 10 most important articles about Upwork

A to Z View - All Upwork Test Answers

Upwork Fiber Optics Test Answer

1. For a step index fiber, relationship between numerical aperture (NA) and coupling efficiency (ηc) is ________.
Answers: • b

2. Mirrors are placed in LASER optical sources to maintain conditions for ________.
Answers: • amplification

3. Optical bandwidth (OB) relates to electrical bandwidth (EB) when
Answers: • OB>EB

4. What is the thermal noise current it in a resistor R expressed in its mean square value?

where, K is Boltzmann's constant, T is absolute temperature and B is the bandwidth
Answers: • c

5. For a profile parameter (α)=1, the profile shape of refractive index for a graded index fiber will be _______.
Answers: • parabolic

6. The rays which travel in a helical path through an optical fiber are called ______.
Answers: • skew rays

7. Dark spot defects (DSD's) occur in:
Answers: • Fiber LASER

8. What happens when dispersion occurs?
Answers: • Output transmitted pulse gets completely eliminated

9. Silicon reach through avalanche photodiodes has _______.
Answers: • maximum absorption of electrons

10. The vapor-phase deposition technique is used to produce _______.
Answers: • fiber-rich glasses

11. Scattering losses happen due to:
Answers: • imperfections in glass manufacturing process

12. Graded-index fibers have:
Answers: • None of these

13. Dispersion in optical fibers causes distortion in _______.
Answers: • digital signals only

14. The LASER is a/an
Answers: • incandescent device

15. SONET is _________.
Answers: • Silicon optical network

16. In p-i-n photodiodes "i" stands for:
Answers: • Intrinsic

17. Dispersion is the lowest in a________.
Answers: • Multimode graded-index fiber

18. Superluminescent LED's are preferred because of _______.
Answers: • low output power

19. Total internal reflection takes place at angles ________.
Answers: • greater than the critical angle

20. LED is more suitable for analog transmission because of its _______.
Answers: • modulation property

21. When optical power is incident on the photo detector during the 0 bit period, then the system is said to exhibit _______.
Answers: • a zero extinction ratio

22. Which of the following is a fiber dispersion measurement method?
Answers: • Time domain measurement

23. Germanium photodiodes are generally not preferred in the optical fiber system because of _________.
Answers: • large dark current

24. Which one of the following is a type of non-linear scattering?
Answers: • Ultraviolet scattering

25. Refer to the figure above.

The critical angle at the core cladding interface is given by:
Answers: • c

26. Intersymbol interference (ISI) in optical fibers occurs due to ______.
Answers: • scattering

27. Near-field scanning method is used to measure:
Answers: • Fiber attenuation

28. Which phenomenon does not let light rays escape an optical fiber?
Answers: • Total internal diffraction

29. Quantum efficiency (η) is defined as
Answers: • c

30. Which of the following is an Optical System Design Software?
Answers: • Photonic Transmission Design Suite (PTDS)

31. COBRA (commutateur optique binaire rapide) is an ________.
Answers: • optical detector

32. For a multimode optical graded index fiber, the profile parameter (α) will be equal to:
Answers: • ∞

33. What would the optical return loss (ORL) be defined as when r-fresnal reflection occurs at a fiber-air interface?
Answers: • ORL= -20log10r

34. When microwave frequency rather than radio frequency subcarriers are employed, the strategy is usually referred to as ______.
Answers: • Code-division multiplexing

35. FDDI can support a data rate of
Answers: • 100 Mbps

36. Numerical aperture (NA) is related to the refractive indexes of core (n1) and cladding (n2) when,
Answers: • b

37. What does TPON stand for?
Answers: • Telephony on a polarized optical network

38. Light emitting diodes (LED's) are:
Answers: • None of the above

39. A multimode graded index fiber exhibits total pulse broadening of 0.2 µsec over a distance of 10Km. Estimate the maximum possible bandwidth assuming that there is no inter-symbol interference.
Answers: • 1 MHZ

40. Homodyne detection is used for _______.
Answers: • incoherent systems

41. Avalanche photodiodes are ________.
Answers: • more sensitive than simple photodiodes

42. Hydrogen absorption by optical fiber causes _______.
Answers: • an increase in optical fiber losses

43. For an ideal photo detector, the absorption coefficient must be ______.
Answers: • large

44. Rayleigh scattering is a ________.
Answers: • non-linear scattering

45. FDDI is _______.
Answers: • Fiber distributed data interface

46. Macro bending losses in optical fibers can be reduced by designing the fibers with ________.
Answers: • a fiber glass

47. Metallic impurities are eliminated from optical fiber by:
Answers: • Vapor axial deposition (VAD) method

48. The information carrying capacity of optical fibers is in the range of:
Answers: • MHZ

49. The first generation optical fibers are fabricated from:
Answers: • Gallium aluminum arsenide alloys

50. The Nd:YAG LASER is a/an_______.
Answers: • injection laser

51. Optical time domain reflectometry (OTDR) is a/an ________.
Answers: • attenuation measurement technique

52. What is the relationship between refractive index (n1) of core and refractive index (n2) of cladding for an optical fiber?
Answers: • n1 < n2

53. SOLITON is a/an ______.
Answers: • type of optical fiber

54. What is signal attenuation in an optical fiber where P1=Input power and P0=Output power
Answers: • c

55. Index optical fibers are sometimes referred to as:
Answers: • Homogenous core fibers

56. IEEE 802.5 is a/an ________.
Answers: • Token ring

57. The cutback technique is a/an _______.
Answers: • refractive index measurement technique

58. The refractive index is defined as the ratio of ____________.
Answers: • the velocity of light in the medium to the velocity of sound in a vacuum

59. The population inversion phenomenon in optical sources occurs when _________.
Answers: • None of the above

60. Intermodal dispersion is less in a __________.
Answers: • Multimode step index fiber

61. The fiber gyroscope is an ______.
Answers: • Intrinsic fiber sensor

62. One polarization maintaining fiber operates at a wavelength of 1.5 µm and has a beat length of 0.6mm. Its modal birefringence is given by _______.
Answers: • 1.5 x 10-3

63. The output power of a LASER is greater than that of a LED because of _____.
Answers: • spontaneous emission

64. Dispersion is low in the __________.
Answers: • Multimode step index fiber

65. Surface emitter LEDs have high radiance because _______.
Answers: • of n-type diffusion into the p-type substrate

66. LASER stands for:
Answers: • Light amplification by straight emission of radiation

67. Dark line defects (DLDs) occur when:
Answers: • mobile impurities are displaced into the active region of LASER

68. Germanium avalanche photodiodes can be used for _______.
Answers: • longer wavelength operation

69. Which of the following is a characteristic of an injection LASER?

Answers: • Amplification

No comments:

Post a Comment