Fiber Optics MCQs

Fiber Optics MCQs

The following Fiber Optics MCQs have been compiled by our experts through research, in order to test your knowledge of the subject of Fiber Optics. We encourage you to answer these 60+ multiple-choice questions to assess your proficiency.
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1: Rayleigh scattering is a ________. 

A.   non-linear scattering

B.   differential scattering

C.   cumulative scattering

D.   linear scattering

2: What does TPON stand for?

A.   Telephony on a pure optical network

B.   Telephony on a plastic optical network

C.   Telephony on a polarized optical network

D.   Telephony on a passive optical network 

3: When microwave frequency rather than radio frequency subcarriers are employed, the strategy is usually referred to as ______.

A.   Time division multiplexing

B.   Frequency division multiplexing

C.   Code-division multiplexing

D.   Subcarrier multiplexing (SCM) 

4: Quantum efficiency (η) is defined as

A.   a

B.   b

C.   c

D.   d 

5: The refractive index is defined as the ratio of ____________.

A.   the velocity of light in a vacuum to the velocity of light in the medium

B.   the velocity of light in the medium to the velocity of sound in a vacuum

C.   the velocity of light in the medium to the velocity of light in a vacuum 

6: 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 _______.

A.   1.5 x 10-3

B.   3.5 x 10-3

C.   2.5 x 10-3

D.   4.5 x 10-3 

7: The Nd:YAG LASER is a/an_______.

A.   non semiconductor laser

B.   semiconductor laser

C.   injection laser

D.   directional laser 

8: 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

A.   5 MHZ

B.   2.5 MHZ

C.   10  MHZ

D.   1 MHZ 

9: Which phenomenon does not let light rays escape an optical fiber?

A.   Total internal reflection

B.   Total internal refraction

C.   Total internal diffraction

D.   Total internal attenuation 

10: What is signal attenuation in an optical fiber where P1=Input power and P0=Output power

A.   a

B.   b

C.   c

D.   None of the above 

11: Surface emitter LEDs have high radiance because _______

A.   a hemisphere of n type GaAs is formed around a diffused p-type region

B.   of p-type diffusion into the n-type substrate  

C.   it restricts the emission to a small active region

D.   of n-type diffusion into the p-type substrate 

12: Optical bandwidth (OB) relates to electrical bandwidth (EB) when

A.   OB<EB

B.   OB=EB

C.   OB>EB

D.   OB≥EB 

13: Metallic impurities are eliminated from optical fiber by:

A.   Vapor axial deposition (VAD) method

B.   Modified chemical vapor deposition (MCVD)method

C.   Vapor-phase oxidation method

D.   Plasma-activated chemical vapor deposition (PCVD)method 

14: IEEE 802.5 is a/an ________.

A.   Ethernet

B.   Token bus

C.   Token ring

D.   Token star 

15: Graded-index fibers have:

A.   a constant refractive index in the core

B.   a variable refractive index in the cladding

C.   a variable refractive index in the core

D.   None of these 

16: What would the optical return loss (ORL) be defined as when r-fresnal reflection occurs at a fiber-air interface?

A.   ORL= -10log10r

B.   ORL= -20log10r

C.   ORL= -30log10r

D.   ORL= -10loge

17: Optical time domain reflectometry (OTDR) is a/an ________.

A.   attenuation measurement technique

B.   refractive index measurement technique

C.   field measurement technique

D.   core diameter measurement technique 

18: Intermodal dispersion is less in a __________.

A.   Multimode step index fiber

B.   Multimode graded index fiber

C.   Single mode step index fiber

D.   Single mode graded index fiber

19: Scattering losses happen due to:

A.   a rise in temperature

B.   imperfections in glass manufacturing process

C.   humidity

D.   bending of fiber

A.   a

B.   b

C.   c

D.   d

21: Avalanche photodiodes are ________.

A.   less sensitive than simple photodiodes

B.   more sensitive than simple photodiodes

C.   cheaper than simple photodiodes

D.   less complex in structure than simple photodiodes 

22: Dispersion is the lowest in a________.

A.   Multimode step-index fiber

B.   Multimode graded-index fiber

C.   Single-mode step-index fiber

D.   Silicon fiber 

23: Dispersion is low in the __________.

A.   Multimode step index fiber

B.   Single mode step index fiber

C.   Two mode step index fiber

D.   None of the above 

24: SOLITON is a/an ______

A.   type of optical fiber

B.   optical source

C.   optical detector

D.   pulse traveling in optical fiber 

25: The vapor-phase deposition technique is used to produce _______.

A.   fiber-rich glasses

B.   silica-rich glasses

C.   oxide-rich glasses

D.   carbonate-rich glasses

26: For an ideal photo detector, the absorption coefficient must be ______.

A.   low

B.   zero

C.   one

D.   large 

27: COBRA (commutateur optique binaire rapide) is an ________.

A.   optical fiber

B.   optical source

C.   optical detector

D.   optical switch 

28: The LASER is a/an

A.   incoherent device

B.   switching device

C.   threshold device

D.   incandescent device 

29: Mirrors are placed in LASER optical sources to maintain conditions for ________.

A.   incoherence

B.   amplification

C.   modulation

D.   coherence

30: For a multimode optical graded index fiber, the profile parameter (α) will be equal to:

A.   ∞

B.   Zero

C.   1

D.   2 

31: FDDI can support a data rate of

A.   10  Mbps

B.   10 Gbps

C.   100 Mbps

D.   1000 Mbps

32: Intersymbol interference (ISI) in optical fibers occurs due to ______.

A.   refraction

B.   scattering

C.   bending

D.   dispersion 

33: When optical power is incident on the photo detector during the 0 bit period, then the system is said to exhibit _______.

A.   a non-zero extinction ratio

B.   a zero extinction ratio

C.   an infinity extinction ratio

D.   an infinity absorption ratio 

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

A.   triangular

B.   parabolic

C.   step

D.   circular 

35: Which of the following is an Optical System Design Software?

A.   MATLAB

B.   COMSIM

C.   Photonic Transmission Design Suite (PTDS)

D.   ORCAD 

36: Which one of the following is a type of non-linear scattering?

A.   Stimulated Raman scattering (SRS)

B.   Rayleigh scattering

C.   Mie scattering

D.   Ultraviolet scattering 

37: The rays which travel in a helical path through an optical fiber are called ______.

A.   refracted rays

B.   reflected rays

C.   infra-red rays

D.   skew rays 

38: The cutback technique is a/an _______.

A.   attenuation measurement technique

B.   refractive index measurement technique

C.   impurity measurement technique

D.   frequency measurement technique 

39: The first generation optical fibers are fabricated from:

A.   Silica

B.   Oxides

C.   Gallium aluminum arsenide alloys

D.   Plastic 

40: Which of the following is a fiber dispersion measurement method?

A.   Time domain measurement

B.   Interferometric method

C.   Refracted near field method

D.   Reflected near field method 

41: Which of the following is a characteristic of an injection LASER?

A.   Frequency Chirp

B.   Amplification

C.   Frequency modulation

D.   Output power

42: The population inversion phenomenon in optical sources occurs when _________.

A.   the population of atoms in the upper energy level is greater than in the lower energy level

B.   the population of atoms in the lower energy level is greater than in the upper energy level

C.   the population of atoms in the upper and lower energy levels is equal

D.   None of the above 

43: Total internal reflection takes place at angles ________.

A.   greater than the critical angle

B.   less than the critical angle

C.   equal to the critical angle

D.   None of the above 

44: The output power of a LASER is greater than that of a LED because of _____.

A.   stimulated emission

B.   spontaneous emission

C.   straight emission

D.   None of the above 

45: Index optical fibers are sometimes referred to as:

A.   Homogenous core fibers

B.   Heterogeneous core fibers

C.   Long fibers

D.   Short fibers 

46: Germanium avalanche photodiodes can be used for _______.

A.   longer wavelength operation

B.   shorter wavelength operation

C.   low output power operation

D.   minimum noise operation 

47: LASER stands for:

A.   Light amplification by spontaneous emission of radiation

B.   Light amplification by stimulated emission of radiation

C.   Light amplification by straight emission of radiation

D.   None of the above 

48: What is the thermal noise current it in a resistor R expressed in its mean square value?
where, K is Boltzmanns constant, T is absolute temperature and B is the bandwidth

A.   a

B.   b

C.   c

D.   d 

49: Macro bending losses in optical fibers can be reduced by designing the fibers with ________.

A.   a smaller refractive index difference

B.   a fiber glass

C.   a silica glass

D.   a larger refractive index difference 

50: LED is more suitable for analog transmission because of its _______.

A.   linearity

B.   bandwidth (spectrum)

C.   modulation property

D.  

output power