BSECE Board Examination Reviewer in Communications Engineering - Fiber Optics
1. Who
made
the
first
documented prediction that
laser light was possible?
a) Ray
b) Edison
c) Einstein
d) Maiman
main
cause
of
attenuation in an optical fiber
is .
a)
Resistance
and
capacitance
b)
Scattering
and
absorption
c) Wavelength
d) Ideal waveguide
7. Which of the following is
13. Where can one found a
not an advantage of optical
fiber?
a) Low attenuation
b) Large bandwidth
c) Immunity to lightning
d) Cabling and splicing
simplicity
fiber-to-detector connector?
a) Transmitter
b) Analog transmitter circuit
block
c) Light emitting diodes circuit
block
d) Receiver
8. What devices may be used
14. Which of the following is
as
an
optical
transmitter?
a) Photo diode
b) Bulb
c) Laser
d) Sun
not a major section required
by laser? a) Feedback
b) Output
c) Exciter
d) Monitor
2. The
fiber
15. Which of the following has
3. What is the spreading of
9. The glass inside the fiber
energy in time, which is
caused by differing light
wavelengths?
a) Fresnel refraction
b) Chromatic dispersion
c) Modal refraction
d) Absorption
core
must
have
a(n)
index of refraction than the
index of refraction of cladding
surrounding the fiber.
a) Higher
b) Lower
c) Varying
d) Equal
4. Which of the following
is
not an application of laser?
a) Planting
b) Communications
c) Surveying
d) Medical applications
5. What is the critical angle (of
incidence) at a glass/fusedquartz interface?
a) 45°
b) 63.6°
c) 76.7°
d) 30°
6. What parts of the body are
most sensitive
damage? a) Hair
b) Teeth
c) Nails and teeth
d) Eye and skin
to
laser
10. The index of refraction of
the cladding is
the
index of refraction of the
core.
a) Varies with
b) Equal to
c) Less than
d) Greater than
11.(Nov 1997) Band of light
waves that are too short to be
seen by human eye.
a) Amber
b) Visible
c) Ultraviolet
d) Infrared
12.Which of the following can
be used to reduce the
attenuation of a cable bend?
a) Adding additional bends
b) Using repeater
c) Increasing the bend
radius
d) Decreasing the bend
radius
the longest wavelength?
a) Fuschia
b) Green
c) Blue
d) Red
16. Which
of the following
does not contribute to a
coupling mismatch between
two optical fibers?
a) Sepatation resulting in light
scattering
b) Improper alignment
c) Connecting ends not
parallel
d) Modal dispersion
17.A wide-band analog fiberoptic receiver’s passband is
limited to .
a) Increase the S/N ratio
b) Amplify the noise
c) Amplify the input signal
d) Improve the bandwidth
18.A fiber core is glass with
n=1.5.
Calculate
the
reflectivity (in percent) from
air.
a) 4%
b) 16%
c) 15%
d) 8%
© Copyright BSECE Online Board Examination Reviewer 2009.
BSECE Board Examination Reviewer in Communications Engineering - Fiber Optics
19. What part of the optical
25. It is t5he scattering of
31. The wavelength of red in
fiber has the smallest outer
diameter?
a) Plastic fiber’s jacket
b) Braided copper core
c) Glass fiber’s core
d) Glass fiber’s cladding
some of the light energy
when monochromatic light is
passed through a medium
such as glass.
a) Raman effect
b) Rigid scattering
c) Huygen’s principle
d) Miller effect
the visible light spectrum is
around .
a) 530 nm
b) 1200 nm
c) 450 nm
d) 700 nm
20. Which of the following is
not used as an optical
detector?
a) Photodiode
b) PIN diode
c) ILD
d) Avalanche photodiode
21. The ration of the number
of photoelectrons collected to
the number of incident
photons per unit time.
a) Quantum efficiency
b) Photonic
c) Irradiance
d) Responsivity
26. Which of the following is a
coherent light source in fiber
optics?
a) LASER
b) LED
c) Sun
d) Bulb
32. It is a measure of the
optical fiber’s light gathering
capabilities.
a) Responsivity
b) Expansion
c) Numerical aperture
d) Dispersion
type of optical
transmitter
requires
no
cladding on the fiber?
a) Led
b) Pin diode
c) Laser
d) Photo diode
33.(Mar 1996) An absorption
loss caused by valence
electrons in the silica material
from
which
fibers
are
manufactured.
a) Ultraviolet absorption
b) Ion resonance absorption
c) Infrared dispersion
d) Modal dispersion
28. Responsivity
34. Which is not an advantage
27. What
22. Who was the first person
who actually produced laser
light?
a) Maiman
b) Einstein
c) Edison
d) Townes
is
an
elementary
quantity of radiant energy,
which can be considered to
be particles of light.
a) Optimons
b) Electrons
c) Lumens
d) Photons
is
a
parameter of the , in fiberoptic system.
a) Receiver
b) Connectors
c) Transmitter
d) Cable
23. It
24.A way of reducing the
attenuation in a fiber-optic
cable assembly.
a) All of the above
b) Polishing the fiber ends
c) Using the least number of
connectors
d) Using ferrules to align the
fiber ends
of optical fiber?
a) Broadband
b) No cross talk
c) Small
d) Cheap
35. Which of the following is a
29.(Nov 1998) One of the
advantages of fiber optic
which is referred to the
volume of capacity of signals
it can carry. a) Weight
b) Physical size
c) Security
d) Bandwidth
30.A type of fiber-optic
connector is called
.
a) Graded fiber
b) Splicer
c) Step fiber
d) Multifiber
major standard for lasers?
a) Federal 2020
b) ANSI Z136
c) Federal 4010
d) ANSI R232
36. Which of the following is
contained in a fiber optic
transmitter?
a)
Fiber-to-detector
connector
b) Light source
c) Light detector
d) An output circuit
37. Light at 1.55 µm in air has
what energy (in eV)?
a) 1.0 eV
b) 0.6 eV
c) 1.21 eV
d) 0.8 eV
© Copyright BSECE Online Board Examination Reviewer 2009.
BSECE Board Examination Reviewer in Communications Engineering - Fiber Optics
38. The speed of lightwave in
fiber optic cable is around
.
a) 300,000 mi/hr
b) 186 mi/hr
c) 300,000,000 m/s
d) 300,00 m/s
39.(Apr 1997) A noncoherent light source for
optical
communications
system.
a) LED
b) PIN diode
c) APD
d) ILD
44.What is the most common
type of damage to the skin by
laser radiation?
a) Erythema
b) Excema
c) Espedema
d) Burn
51.Light can be thought of as
an electromagnetic wave or
as particles called .
a) Electrons
b) Protons
c) Quantum
d) Photons
45.(Mar 1996) The dielectric
material of an optical fiber
surrounding the core
a) Cladding
b) Cover
c) Armor
d) Shield
52.(Apr 1998) Which of the
following colors of light rays
has the shortest wavelength?
a) Violet
b) Red
c) Blue
d) Yellow
53.The rays comprising a
mode that all passes through
the longitudinal, or z-axis of
the fiber core, are called
.
a) Convergent rays
b) Meridional rays
c) Divergent rays
d) Skew rays
46. The amount of power per
40.One of the following is not
a basic part of a fiber-optic
communication link?
a) Light detector
b) Speaker
c)
A
fiber-to-detector
connector
d) Light source
41.(Apr 1998) What does a
light traveling in air optical
fiber follow?
a) Millman
b) Snell’s
c) Huygen
d) Maxwell
42.(Nov 1997) The most
common device used as a
light detector in fiber optic
communication system.
a) LED
b) APDs
c) Darlington phototransistor
d) PIN diode
43.(Nov 1997) Loss due to
the diffraction of light when it
strikes on the irregularities
formed
during
the
manufacturing process of the
fiber optics.
a) Absorption loss
b) Bending loss
c) Rayleigh scattering loss
d) Attenuation
unit area in optical fiber is
called .
a) Irradiance
b) Discerneance
c) Permeance
d) Reflectance
47. Which of the following is
not a class of laser radiation?
a) Class X
b) Class IV
c) Class I
d) Class II
54.A fiber-optic core is made
of
.
a) Water
b) Krypton
c) Glass
d) Diamond
48. Which of the following is
an advantage of fiber-optic
cable
over
conventional
cable?
a) Interference immunity
b) Wider bandwidth
c) Light weight
d) All of the above
49.(Apr 1997) Type of fiber
that has the highest modal
dispersion.
a) Graded index multimode
b) Graded index mode
c) Step-index multimode
d) Step-index single mode
50.(Apr 1997) Fiber
cable
operates
frequencies.
a) 20 MHz
b) 2 GHZ
c) 200 MHz
d) 800 THz
55. The information that can
be transmitted over a fiberoptic communication link?
a) Audio frequency
b) All of the above
c) Video signal
d) Pulses and data
56. Which of the following is
not a source of attenuation in
a fiber-optic cable?
a) Dispersion
b) Conduction
c) Absorption
d) Scattering
optic
near
© Copyright BSECE Online Board Examination Reviewer 2009.
BSECE Board Examination Reviewer in Communications Engineering - Fiber Optics
57. It is an optical network
62. Compute the power for an
transmission
has
an
connectivity.
a) STS
b) SDH
c) PDH
d) SONET
ideal 1550-nm light source
that generates 20 billion
photons per second.
a) 2.56 nW
b) 14.6 nW
c) 12.5 nW
d) 13 nW
of the light detector
increases the fall time.
a)
Decreasing
the
bandwidth
b) Increasing the coupling
loss
c) Decreasing the rise time
d) Increasing the rise time
63. What
69. What is the type of fiber,
64. What are the rays which
characterized by a
core
which has a completely
uniform distribution of the
index of refraction throughout
its bulk?
a) Step-index fiber
b) Meridional fiber
c) Graded-index fiber
d) Multi-grade fiber
standard that
international
58.(Nov 1996) 1 micron is
equal to
meter(s).
a) 10^(-6) m
b) 10^9 m
c) 10^(-3) m
d) 10^6 m
59.A 1-km long optical fiber in
air is made of fiber core with
an index of refraction of 1.52
and a cladding with an index
of
refraction
of
1.49,
determine the acceptance
angle.
a) 30°
b) 35°
c) 60°
d) 17.5°
60.(Nov 1997) The core of
the optical fiber has
.
a) A lower index of refraction
than the cladding
b) A higher index of
refraction than the cladding
c) A medium index of
refraction
d) A lower index of refraction
than air
61. Which is the relationship
between
the
angle
of
incidence and the angle of
reflection?
a) Decreasing
b) They are equal
c) Increasing
d) Varying
is the angle of
refraction when the angle of
incidence is 35° traveling
from glass (n=1.4) to the air?
a) 60.3°
b) 48.5°
c) 36.4°
d) 53.4°
do not pass though the core
axis, but follow a spiral path
of reflecting segments down
the fiber core?
a) Convergent rays
b) Skew rays
c) Divergent rays
d) Meridional rays
65. Which
of the following
cannot be sent over a fiberoptic communication link?
a) Cable TV signals
b) Telephone messages
c) Computer data
d) Electric power
66.(Nov 1998) An advantage
of optic fiber rejecting an
induced noise signals from
magnetic field or solar storms
flux.
a) Cross talk
b) Shielding
c) Electric hazard
d) Immunity to noise
67. The
determines if a
light ray will stay within the
transmitting medium or be
refracted from it.
a) Responsivity
b) Modal dispersion
c) Critical angle
d) Radiance
68.
70. Which of the following is
not a integral part of a fiberoptic communication link?
a) Optical fiber
b) Light detector
c) Light source
d) RS-232 interface
71.(Mar 1996) It is made from
semiconductor material such
as
aluminum-galliumarsenide or gallium-arsenidephosphide.
a) APD
b) Light emitting diode
c) Positive-intrinsic-negative
d) Injection laser diode
72.The first device used to
transmit voice using light as a
carrier is called .
a) Photophone
b) Phonograph
c) Lyncompex
d) Edison bulb
73.(Nov 1996) An object
farther from a converging
lens than its focal point
always has an image.
a) The same in size
b) Virtual
c) Smaller size
d) Inverted
© Copyright BSECE Online Board Examination Reviewer 2009.
BSECE Board Examination Reviewer in Communications Engineering - Fiber Optics
74. What wavelengths exhibit
the least loss for transmission
in glass?
a) 12-15.5 microns
b) 5-7 microns
c) 10-50 microns
d) 1.3-1.5 microns
75. The index of refraction of
the core in a fiber-optic cable
is
the index of
refraction of the cladding.
a) Equal to
b) Summation of
c) Greater than
d) Less than
80.(Nov 1996) The loss in
signal power as light travels
down a fiber is
a) Absorption
b) Scattering
c) Attenuation
d) Propagation
81.What is a wave or pulse
that does not disperse or lose
its shape as it propagates
through a medium?
a) Incoherent source
b) Photon
c) Coherent source
d) Soliton
82. Which
76.(Nov 1996) The different
angles of entry of light into an
optical
fiber
when
the
diameter of the core is many
times the wavelength of the
light transmitted is known as
. a) Mode
b) Emitter
c) Sensor
d) Refraction
77. An optical fiber is made
with a core of flintglass
(n=1.62) and a cladding of
crown glass (n=1.51). Find
the critical angle at the
core/cladding interface.
a) 70.8°
b) 45°
c) 68.8°
d) 30°
78. What is not a way of
representing a radiometric
measure of power?
a) Milliwatts per square
centimeter
b) Lumens per watt
c) Watt
d) Microwatts per steradian
79. Which of the following is
used to send multiple signals
over a single optical fiber?
a) Sync-encoding
b) TDM
c) FDM
d) Manchester code
of the following
affects the bandwidth of an
optical fiber?
a) Splicing
b) Modal dispersion
c) Refractive index
d) Material dispersion
83. At he fiber optic receiver
the light detector
.
a) Has an optical output
b) Can not have a coupling
loss
c) Acts as a light detector
d) Has an electrical signal
as an output
84. Which of the following is a
not a kind of dispersion that
exists in a fiber?
a) Wavelength dispersion
b) Chromatic dispersion
c) Harmonic dispersion
d) Intermodal dispersion
85. The refractive index of
glass is around
a) 1.33
b) 0.50
c) 1.50
d) 1
.
86.A figure of merit that is
used to describe the light
gathering or light collecting
ability of an optical fiber.
a) Reflectivity
b) Responsivity
c) Numerical aperture
d) Permeance
87.(Nov 1997) Calculate the
energy of the photon of
infrared light energy at 1.55
µm.
a) 1.6 x 1019 J
b) 1.9 x 10-14 J
c) 1.28 x 10-19 J
d) 1.22 x 10-16 J
88. An optical fiber is silicon
glass
composed
layers. a) 5
b) 1
c) 4
d) 3
of
89. What is the most common
type of damage to the human
eye by laser radiation?
a) Retinasus
b) Ultraviolet radiation
c) Cormeasis
d) Cataract
90. What
is
the
power
delivered by a laser whose
output energy in 2 second is
10 joules
a) 10 W
b) 5 W
c) 15 W
d) 20 W
91. The ratio of the sines of
the angles of the incident and
refracted waves is
to
the ratio of the velocities of
light in the mediums causing
the refraction.
a) Less than
b) Equal
c) Not related
d) Greater than
© Copyright BSECE Online Board Examination Reviewer 2009.
BSECE Board Examination Reviewer in Communications Engineering - Fiber Optics
92. Which of the following is
99. An optical medium with a
not a source of light in fiber
optic communication?
a) Laser
b) APD
c) ILD
d) LED
small core diameter in which
only
one
mode
can
propagate. a) Single-mode
fiber
b) Multi-mede fiber
c) Laser
d) Led
93. Which of the following is
the
least
important
characteristic of a fiber-optic
light source?
a) Bandwidth
b) Light intensity
c) Hue
d) Resistance
100. Which of the following
will indicate the distance to a
faulty fiber-optic connection?
a) Fiber-optic power meter
b) Optical time-domain
reflectometer
c) Fiber-optic light source
d) Digital voltmeter
94. What is the ratio of the
speed of light in free space to
the speed of light in another
medium?
a) Index of refraction
b) Velocity factor
c) Index of reflecrion
d) Dielectric constant
95. What is a coherent light?
a)
b)
c)
d)
Light waves in air
Light waves varying
Light waves in phase
Light waves out of phase
96. What
term
is
commonly used in
optics?
a) Optical fiber
b) Light pipe
c) Fiber-optic cable
d) Light cable
not
fiber
97. What carrier frequencies
are used in optical
systems?
a) Infrared
b) All of the above
c) Ultraviolet
d) Visible
fiber
98. The measurement of the
strength of the light source is
called .
a) Permeance
b) Reflectance
c) Scerneance
d) Radiance
© Copyright BSECE Online Board Examination Reviewer 2009.
ARVIN