Past ExamsRwanda ICT preparation

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Fiber Optics

15 free questions with worked answers, and 78 more in the full bank.

Free questions

While analyzing an OTDR trace of a newly installed 5km single-mode link, you see a sharp spike upwards followed by a drop in the trace level. What physical event does this signature represent?
3 marks · Medium
An OTDR trace shows an event at 4km that appears to be a "gainer" (the trace goes up, showing negative loss). What is the actual physical cause of a gainer in an OTDR trace?
4 marks · Hard
You are shooting an OTDR trace on a short 100m patch cord but cannot see the connector at the far end clearly due to the initial pulse width. What setting should you adjust?
1 mark · Easy
You perform a Tier 1 certification (OLTS) on a multi-mode fiber link. The measured loss is 2.5 dB, but the calculated loss budget is 1.8 dB. What is the immediate result?
3 marks · Medium
When measuring Optical Return Loss (ORL) on a single-mode video link, the meter reads 20 dB. The specification requires >45 dB. What does the 20 dB reading indicate?
4 marks · Hard
A technician scopes an SC/UPC connector and sees a large dark smudge directly over the core of the fiber. What is the correct next step?
1 mark · Easy
Under a fiber microscope, you observe permanent pitting and scratches crossing the 9-micron core of a single-mode LC connector, even after multiple wet/dry cleanings. What is the impact on performance?
3 marks · Medium
During a campus backbone installation, a contractor pulls a 24-strand outdoor loose-tube cable around a 90-degree conduit bend. The conduit diameter is 2 inches, and the cable diameter is 0.5 inches. The contractor bends the cable over a 4-inch radius. Why is this a problem?
3 marks · Medium
You are terminating a 12-strand distribution cable. According to the standard TIA-598 color code, what is the color of fiber #6?
1 mark · Easy
A crew is pulling a heavy armored OSP cable using a tugger. They exceed the maximum rated pulling tension of 600 lbs for a few seconds. Later, tests show high attenuation across all fibers. What physically happened inside the cable?
4 marks · Hard
A data center needs to upgrade a 100-meter server-to-switch link to 40GBASE-SR4. What type of fiber and wavelength should they select for the most cost-effective solution?
3 marks · Medium
A telecom provider is troubleshooting a 60km long-haul single-mode link. The link passes perfectly at 1310nm but shows 8 dB of excess loss at 1550nm. What is the most likely physical cause?
4 marks · Hard
A technician spliced two pigtails in a splice tray. The link passes the initial OTDR test. Two days later, the link drops. When the tech opens the tray, the link suddenly comes back up. What is the likely issue?
3 marks · Medium
You are designing a DWDM network using the ITU-T G.694.1 grid. The system uses a 100 GHz channel spacing. Approximately how much wavelength separation exists between adjacent channels?
4 marks · Hard
A technician accidentally patches a CWDM transceiver module transmitting at 1470nm into a DWDM multiplexer designed for the C-band. What will happen?
3 marks · Medium

More Fiber Optics questions (page 2 of 2)

Answers and explanations are in the full bank.