1
Fiber Installation and Activation
Questions and Correct Answers
Question: What is the Fiber-optic cable term for optical transport that is
restricted to one path (mode) for light propagation through the core of an
optical fiber?
Answer: Single Mode Fiber
Question: A type of optical fiber with large core diameters which allow
multiple modes, or paths, upon which the optical signal travels is known
as what?
Answer: Multi - Mode Fiber
Question: In fiber-optic terminology, what is "window" ?
Answer: Refers to a center optical wavelength, as well as a range of
wavelengths on either side of the center wavelength
Question: What are the four standard optical windows?
Answer: 850 nm, 1,300 nm, 1,550 nm, and 1,625 nm.
Question: What window is exclusively used for multimode fiber?
Answer: 850 nm
Question: What is an Erbium-doped fiber amplifier (EDFA)?
Answer: An optical amplifier that uses active erbium-doped fiber and a
pump source (laser) to boost or amplify the optical signal?
Question: What are the three basic components of all fiber-optic
communications networks?
Answer: (1) an optical transmitter with a light source; (2) the optical fiber
(3) an optical receiver with a photodetector.
Pretest - Stuvia US
,2
Question: What characteristic of a fiber-optic cable enhances the
security of signals being transported in the network?
Answer: Fiber optics are typically made of glass which is a dielectric
material which is basically immune to EMI and RFI
Question: What telecommunication standard designation encompasses
all things voice, video, and data?
Answer: ITU Telecommunications Standardization Sector ITU-T
Question: Single -mode fiber-optic cable is optimized to transport which
wavelengths?
Answer: 1310 nm & 1550 nm
Question: An optical fiber consists of what three basic parts?
Answer: Core, Cladding, and Coating
Question: What does the spectral width of a laser or Light Emitting
Diode (LED) define?
Answer: A measurement for the band of wavelengths over which a laser
light source emits its energy, generally measured in nanometers (Nm)
between the half power points of an optical light sources maximum
amplitude at the center frequency Full Width Half Maximum (FWHM)
Question: Which type of laser is ideal for analog, high speed digital, and
optical multiplexing networks because of its high SNR (signal to noise
ratio) and small spectral widths?
Answer: Distributed Feed Back (DFB) laser
Question: What are the two common types of laser diodes used in fiber
optic networks?
Answer: Distributed Feed Back (DFB) lasers and Fabry-Perot (F-P) lasers
Question: What are two types of optical detector used in fiber-optic
networks?
Pretest - Stuvia US
, 3
Answer: Positive-Intrinsic-Negative diode (PIN) & Avalanche Photo Diode
(APD)
Question: What are the two methods used to modulate an optical carrier
?
Answer: Direct Modulation and Indirect Modulation
Question: How is optimal sensitivity in an optical receiver obtained?
Answer: Efficient Coupling to the optical fiber to transfer the maximum
amount of optical power from the optical fiber to the receiver.
Question: Why is the positive -intrinsic - negative (PIN) photo-diode the
most common type of photo-diode used in optical receivers?
Answer: It is relatively inexpensive and can be operated from a standard
power supply.
Question: What is the primary difference between an avalanche photo-
diode (APD) and a positive-intrinsic-negative (PIN) photo-diode?
Answer: APD require a higher voltage power supply and more complex
circuitry
Question: What type of electrical detection can improve the sensitivity
of an optical reliever by as much as 20dB?
Answer: Coherent Detection
Question: Which standards organization is considered to be the creator
of the world's most recognized communications standards, known as
"recommendations?"
Answer: The International Telecommunication Union (ITU).
Question: In which component in a fiber-optics communication system
do changes to the intensity of the optical signal occur?
Answer: The optical transmitter.
Pretest - Stuvia US
Fiber Installation and Activation
Questions and Correct Answers
Question: What is the Fiber-optic cable term for optical transport that is
restricted to one path (mode) for light propagation through the core of an
optical fiber?
Answer: Single Mode Fiber
Question: A type of optical fiber with large core diameters which allow
multiple modes, or paths, upon which the optical signal travels is known
as what?
Answer: Multi - Mode Fiber
Question: In fiber-optic terminology, what is "window" ?
Answer: Refers to a center optical wavelength, as well as a range of
wavelengths on either side of the center wavelength
Question: What are the four standard optical windows?
Answer: 850 nm, 1,300 nm, 1,550 nm, and 1,625 nm.
Question: What window is exclusively used for multimode fiber?
Answer: 850 nm
Question: What is an Erbium-doped fiber amplifier (EDFA)?
Answer: An optical amplifier that uses active erbium-doped fiber and a
pump source (laser) to boost or amplify the optical signal?
Question: What are the three basic components of all fiber-optic
communications networks?
Answer: (1) an optical transmitter with a light source; (2) the optical fiber
(3) an optical receiver with a photodetector.
Pretest - Stuvia US
,2
Question: What characteristic of a fiber-optic cable enhances the
security of signals being transported in the network?
Answer: Fiber optics are typically made of glass which is a dielectric
material which is basically immune to EMI and RFI
Question: What telecommunication standard designation encompasses
all things voice, video, and data?
Answer: ITU Telecommunications Standardization Sector ITU-T
Question: Single -mode fiber-optic cable is optimized to transport which
wavelengths?
Answer: 1310 nm & 1550 nm
Question: An optical fiber consists of what three basic parts?
Answer: Core, Cladding, and Coating
Question: What does the spectral width of a laser or Light Emitting
Diode (LED) define?
Answer: A measurement for the band of wavelengths over which a laser
light source emits its energy, generally measured in nanometers (Nm)
between the half power points of an optical light sources maximum
amplitude at the center frequency Full Width Half Maximum (FWHM)
Question: Which type of laser is ideal for analog, high speed digital, and
optical multiplexing networks because of its high SNR (signal to noise
ratio) and small spectral widths?
Answer: Distributed Feed Back (DFB) laser
Question: What are the two common types of laser diodes used in fiber
optic networks?
Answer: Distributed Feed Back (DFB) lasers and Fabry-Perot (F-P) lasers
Question: What are two types of optical detector used in fiber-optic
networks?
Pretest - Stuvia US
, 3
Answer: Positive-Intrinsic-Negative diode (PIN) & Avalanche Photo Diode
(APD)
Question: What are the two methods used to modulate an optical carrier
?
Answer: Direct Modulation and Indirect Modulation
Question: How is optimal sensitivity in an optical receiver obtained?
Answer: Efficient Coupling to the optical fiber to transfer the maximum
amount of optical power from the optical fiber to the receiver.
Question: Why is the positive -intrinsic - negative (PIN) photo-diode the
most common type of photo-diode used in optical receivers?
Answer: It is relatively inexpensive and can be operated from a standard
power supply.
Question: What is the primary difference between an avalanche photo-
diode (APD) and a positive-intrinsic-negative (PIN) photo-diode?
Answer: APD require a higher voltage power supply and more complex
circuitry
Question: What type of electrical detection can improve the sensitivity
of an optical reliever by as much as 20dB?
Answer: Coherent Detection
Question: Which standards organization is considered to be the creator
of the world's most recognized communications standards, known as
"recommendations?"
Answer: The International Telecommunication Union (ITU).
Question: In which component in a fiber-optics communication system
do changes to the intensity of the optical signal occur?
Answer: The optical transmitter.
Pretest - Stuvia US
