Fiber U Basics

Lesson #8, Fiber Optic Testing

 FOA Reference Guide To Fiber Optics
And Study Guide To FOA Certification

FOA Reference Guide to Fiber Optics

Answers To Chapter Questions

Chapter 8 Quiz - Fiber Optic Testing


    1.    ANS:    F
OTDR testing is not acceptable in place of insertion loss testing in standards due to its different test method.

    2.    ANS:    F
Connectors on the ends of the cables must be included in loss budgets since they will be included in insertion loss tests.

    3.    ANS:    T
The launch cable allows the OTDR to see beyond its dead zone and measure the first connector on a cable.


    4.    ANS:    A
Before installing or testing cables, it's important to know what the projected loss will be to ensure the systems will operate over the fiber and the acceptable loss is known for testing.

    5.    ANS:    D
OFSTP-14 is the standard for MM cable testing.

    6.    ANS:    A
Insertion loss requires and light source at one end and a power meter at the other.

    7.    ANS:    B
MM fiber is usually tested with sources similar to the systems that will use the fiber, LEDs at 850 or 1300 nm. Although some systems at gigabit speeds used VCSEL lasers, testing is still done with LEDs.

    8.    ANS:    C
Systems on singlemode fiber use laser sources, so testing is done with lasers.

    9.    ANS:    C
The "0 dB" reference can be set with one, two or three reference cables.

    10.    ANS:    A
TIA-568 calls for a one cable reference but it's not always feasible, with multifiber plug and jack connectors, for example.

    11.    ANS:    B
The fiber in reference cables must be the same as those in the cable being tested and connectors must be compatible.

    12.    ANS:    A
Attenuation in dB/km times the number of km of length equals loss in dB.

    13.    ANS:    B
By sending out a high-power signal and looking for returned scattered and reflected power, the OTDR works like an optical RADAR.

    14.    ANS:    D
OTDRs can verify splice loss, measure length and find faults in installed cables.

    15.    ANS:    C
Their inability to resolve short cables makes OTDRs of limited use in premises systems.

Next: Lesson 9: Fiber Optic Network Design 

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