You dont have javascript enabled! Please enable it! MCQ in Fiber Optics Communications Part 3 | ECE Board Exam

# MCQ in Fiber Optics Communications Part 3 | ECE Board Exam

This is the Multiples Choice Questions Part 3 of the Series in Fiber Optics Communications as one of the Communications Engineering topics. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize yourself with each and every question compiled here taken from various sources including but not limited to past Board Examination Questions in Electronic Systems and Technologies, Communications Books, Journals, and other Communications References.

#### MCQ Topic Outline included in ECE Board Exam Syllabi

• MCQ in Principles of Light Transmission
• MCQ in Types of Light Sources, Laser, LED
• MCQ in Light Detectors
• MCQ in Modulation and Waveform
• MCQ in System Design
• MCQ in General application
• MCQ in System Bandwidth
• MCQ in Splicing Techniques

#### Continue Practice Exam Test Questions Part 3 of the Series

Choose the letter of the best answer in each questions.

101. SONET stands for

a. System Optical Network

b. Synchronous Optical Network

c. Silica Optic Network

d. System Optical Fiber Net

Explanation:

102. Band loss is

a. A reduction in transmitter power caused by earthโs surface curvature

b. A reduction in strength of the signal caused by folded dipole bends

c. An attenuation increase caused by bends radiating from the side of the fiber

d. All of these

Explanation:

103. Infrared range for fiber optics

a. 400 โ 700 nm

b. 700 โ 1200 nm

c. 300 โ 2000 nm

d. 400 โ 7000 nm

aExplanation:

104. Which of the following is a disadvantage for plastic fiber optics?

a. Noise immunity

b. Electric hazards

c. Higher losses

d. All of these

Explanation:

105. OTDR stands for

a. Optical Time Domain Reflectometer

b. Optical Transmit Direction Return

c. Optical Time Domain Time Regeneration

d. Overtime Direct Reference

Explanation:

106. Which of the following is determined by an OTDR?

a. Distance to trouble

b. Length of fiber

c. Refractive index

d. All of these

Explanation:

107. Under normal condition, a single fiber should not be used for a two-way communication mainly because of

a. Loss

c. Noise

d. Attenuation

Explanation:

108. A single mode optical fiber has a core diameter of _____ nm.

a. 0.1

b. 0.01

c. 0.2

d. 0.05

Explanation:

109. A step-index multimode optical fiber has a core diameter of _____ nm.

a. 0.02

b. 0.2

c. 2

d. 0.002

Explanation:

110. The graded-index multimode optical fiber has a core diameter of _____ nm.

a. 0.5

b. 0.05

c. 0.0005

d. 5

Explanation:

111. Which is not a possible cause of optical fiber loss?

a. Impurities

b. Glass attenuation

c. Stepped index operation

d. Microbending

Explanation:

112. The ratio of the speed of light in a vacuum and the speed of light in the material used.

a. S/N ratio

b. Refractive index

c. Intermodal dispersion

d. Monomode ratio

Explanation:

113. Splicing fibers means

a. Fusion

b. Butt

c. Glue

d. Both fusion and butt

Explanation:

114. An IC that represents a short distance one-way optical communications

a. Optoisolator

b. Insulator

c. Multivibrator

d. Optical IC

Explanation:

115. When light strikes a flat polished end of a fiber, it produces a loss of

a. 14%

b. 4%

c. 10%

d. 1%

Explanation:

116. When light strikes a flat polished end of a fiber, the fiber loss produced can be reduced by

a. Splicing

b. Antireflection coating

c. Insulation jacket

d. All of these

Explanation:

117. In fiber optics, higher-order mode refers to

a. Cladding boundary at high angle

b. Backscattering electromagnetic signals

c. Diffracting signals

d. All of these

Explanation:

118. The following are the cause of light attenuation in fiber optics except

a. Backscattering

b. Absorption

c. Refraction

d. Microbends

Explanation:

119. Why are visible-light LEDs not used for fiber optics?

a. It has high losses

b. It has short wave

c. It has low attenuation

d. It has weak signal

Explanation:

120. Optical cable testers are used for

a. Checking refractive index

b. Light power out of a fiber

c. Non-calibrated light into a fiber

d. Checking maximum distance covered

Explanation:

121. A function of an optic isolator

a. Cancels reflective waves

b. Amplifies signal transmitted

c. Filters unnecessary signals

d. All of these

Explanation:

122. An increase in light intensity produces fast optic switching due to

a. Increase in index of glass

b. Amplification of optical signal

c. High gain

d. Photoconductivity

Explanation:

123. Light traveling in optical fiber follows which of the following principles.

a. Huygenโs principle

b. Reflection theory

c. Light theory

d. Snellโs law

Explanation:

124. Optical fibers for telecommunications are typically about _____ mils thick and consists of a glass core, a glass cladding of lower index of refraction, and a protective coating

a. 5

b. 6

c. 7

d. 8

Explanation:

125. Material dispersion is caused by the

a. Wavelength dependence of the index of refraction

b. Wavelength independence of the index of refraction

c. Dependence of the propagation constant on the mode number

d. Independence of the propagation constant on the mode number

Explanation:

126. Modal dispersion is caused by the

a. Dependence of wavelength on index of refraction

b. Dependence of propagation constant on index of refraction

c. Dependence of the propagation constant on the wavelength

d. Dependence of the propagation constant on the mode number

Explanation:

127. The dominant loss mechanisms in silica fiber are

b. Absorption and Rayleigh scattering

Explanation:

128. The bandwidth of a fiber is limited by

a. Mode

b. Wavelength

c. Dispersion

d. Frequency

Explanation:

129. Fiber bandwidth is generally specified as the

a. Product of the bandwidth and distance

b. Sum of the bandwidth and distance

c. Difference of the bandwidth and distance

d. Quotient of bandwidth and distance

Explanation:

130. The _____ of a detector is the fraction of incident photons that produce a photoelectron or electron-hole pair

a. Responsitivity

b. Photon efficiency

c. Aperture

d. Quantum efficiency

Explanation:

131. In solid-state optical detectors, the excited charge is transported in the solid by

a. Holes and protons

b. Holes and electrons

c. Anion and cation

d. Protons and photons

Explanation:

132. One of the following is not a solid-state optical detector

a. APD

b. PIN

c. PMT

d. Phototransistors

Explanation:

133. Optical detectors are square-law devices because they respond to _____ rather than amplitude

a. Intensity

b. Light

c. Density

d. Photon

Explanation:

134. The _____ is equal to the number of electrons emitted per second times the electron charge

a. Intensity

b. Optical power

c. Photocurrent

d. Responsitivity

Explanation:

135. Which optical detector is used when high sensitivity and bandwidth are required?

a. PMT

b. APD

c. PIN

d. Phototransistor

Explanation:

136. What is the average loss in fiber splice?

a. 0.10 dB

b. 0.15 dB

c. 0.20 dB

d. 0.25 dB

Explanation:

137. Which of the following colors is not found in the visible light wave spectrum?

a. Red

b. White

c. Orange

d. Yellow

Explanation:

138. What is the frequency limit of an optical fiber?

a. 20 GHz

b. 30 GHz

c. 40 GHz

d. 50 GHz

Explanation:

139. The mechanical splice attenuation loss is _____ dB or less

a. 0.1

b. 0.01

c. 0.001

d. 1

Explanation:

140. _____ is applied to protect core and cladding of the fiber

a. Insulation

b. Fiber insulation

c. Silica

d. Polymer jacket

Explanation:

141. The energy of the photon is

a. Directly proportional to its bandwidth

b. Directly proportional to the Planckโs constant

c. Directly proportional to Boltzmannโs constant

d. Inversely proportional to the Planckโs constant

Explanation:

142. Refractive index of glass

a. 1.0

b. 1.2

c. 1.4

d. 1.5

Explanation:

143. Refractive index of diamond

a. 1.0

b. 1.4

c. 1.8

d. 2.0

Explanation:

144. What is the unit of light wavelength?

a. Micrometer

b. Angstroms

c. Mils

d. Fathom

Explanation:

145. How much is the power loss of the fusion splice?

a. 0.1 dB or less

b. 0.01 dB or less

c. 1 dB or less

d. 10 dB or less

Explanation:

146. Used to test a fiber optics splice

a. Spectrum analyzer

b. Oscilloscope

c. Optical power meter

d. Field strength meter

Explanation:

147. A coupler which consists of a series of lenses and a partly reflective surface

a. Beam-splitting coupler

b. Reflective star coupler

c. Fused coupler

d. None of these

Explanation:

148. Reflections in many directions

a. Diffuse reflection

b. Diffraction

c. Scattering

d. Dispersion

Explanation:

149. Commonly used electro-optic crystal for polarization modulation

a. Lithium Niobate

b. Tourmaline

c. Sodium Chlorate

d. Sphalerite

Explanation:

150. Which modulation methods are the most widely used in optical systems?

a. Phase and frequency modulations

b. Polarization modulation and phase modulation

c. Intensity modulation and phase modulation

d. Intensity modulation and polarization modulation

Explanation:

### Complete List of MCQ in Communications Engineering per topic

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