Optical Communications Multiple Choice Questions on “Field Measurements”.
1. ____________ affects both the fiber attenuation and dispersion.
a) Refractive index
b) Micro-bending
c) Connectors
d) Splices
Answer: b
Explanation: Effects such as micro-bending with a resultant mode coupling affect both the fiber attenuation and dispersion. It does not provide the overall characteristics of the transmission link.
2. Which of the following is not included in the optical fiber link measurement test?
a) Attenuation measurement
b) Dispersion measurement
c) Splice loss measurement
d) Receiver sensitivity
Answer: d
Explanation: It is necessary to perform some tests on the optical fiber link to enhance productivity. Apart from receiver sensitivity, other measurement methods are required to test the fiber link.
3. In case of field measurements, the equipment must have ___________ power consumption keeping in mind the battery operation.
a) Low
b) High
c) Negligible
d) Maximum
Answer: a
Explanation: The design criteria allows you to distinguish in parameters required for adaptation of battery operation and equipment handling. The power consumption must be low for an equipment to handle.
4. Which of the following are not considered as environmental conditions required for field measurements?
a) Temperature
b) Humidity
c) Mechanical load
d) Power
Answer: d
Explanation: The equipment must be reliable and provide accurate measurements under extreme environmental conditions such as humidity, temperature and mechanical load. Power is an internal factor.
5. Complicated and involved fiber connection arrangements should be _________ in case of field measurements.
a) Provided
b) Avoided
c) Maximized
d) Minimized
Answer: b
Explanation: The equipment must be connected to the fiber in a simple manner. It should be connected without the need for fine or critical adjustment.
6. Which of the following cannot be used in equipment for field measurements?
a) Fiber
b) Connector
c) External triggering
d) Environmental factor
Answer: c
Explanation: The equipment cannot usually make use of external triggering and regulating circuits between the transmitter and receiver. This is because of their wide spacing on the majority of the optical links.
7. Which sensors are used for alteration of spectral range in equipment?
a) Wide-area photodiodes
b) Circulators
c) Gyrators
d) Photogenic sensors
Answer: a
Explanation: Wide area photodiodes such as silicon, germanium diodes are used for alteration of spectral range. It is generally preferred to have a measurement range from -100 dBm.
8. The handheld optical power meter has a measurement accuracy of ________
a) 0.01 dB
b) 0.25 dB
c) 0.8 dB
d) 1 dB
Answer: b
Explanation: The optical power meter detects the fiber type and switches to optical power measurements. It provides an accuracy of about +(or -) 25 dB.
9. _____________ may be used for measurement of the absolute optical attenuation on a fiber link.
a) Silicon photodiodes
b) InGaAsP photodiodes
c) Optical power meters
d) Gyrators
Answer: c
Explanation: Optical power meter employs cut-back technique. It is used for the measurement of the optical attenuation.
10. A large-area photodiode is utilized in the receiver to eliminate any effects from differing fiber and faces.
a) True
b) False
Answer: a
Explanation: The modulating voltage maintains the equilibrium between the transmitter and the receiver side. A large area photodiode is required to eliminate differing fiber and faces to maintain the equilibrium.
11. Optical time domain reflectometry is also called a backscatter measurement method.
a) False
b) True
Answer: b
Explanation: OTDR technique is used in both on-field and laboratory applications. It is also called a backscatter measurement method as it provides the measurement of attenuation on an optical link down its entire length.
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