FOA CFOT TERMS AND DEFINITIONS A
THRU Z EXAM 2025/2026 QUESTIONS
AND ANSWERS 100% PASS
Watts - ANS What is a linear measure of optical power?
Wavelength - ANS What is the measure of the color of light, usually expressed in
nanometeres (nm) or microns (*m)?
Wavelength Division Multiplexing (WDM) - ANS What do you call a technique of sending
signals of several different wavelengths of light into the fiber simultaneously?
Working Margin - ANS The difference (in dB) between the power budget and the loss budget
(i.e. the excess power margin) is known as what?
Visual Fault Locator (VFL) - ANS A device that couples visible light into the fiber to allow
visual tracing and testing of continuity.
Vertical Cavity Surface Emitting Laser (VCSEL) - ANS A type of laser that emits light vertically
out of the chip, not out of the edge, and is widely used in fast multimode networks.
Transmitter - ANS A device which includes an LED or laser source and signal conditioning
electronics that is used to inject a signal into fiber.
1 @COPYRIGHT 2025/2026
, Total internal reflection - ANS Confinement of light into the core of a fiber by the reflection
off the core-cladding boundary.
Test source - ANS A laser diode or LED used to inject an optical signal into fiber for testing
loss of the fiber or other components.
Test kit - ANS A kit of fiber optic instruments, incl. power meter, source and test accessories
(to measure loss and power)
Test cable - ANS A short single fiber jumper cable with connectors on both ends. This cable
must be made of fiber and connectors of matching type...
Termination - ANS The preparation of the end of a fiber to allow connection to another fiber
or active device.
Talkset - ANS A communication device that allows conversation over unused fibers.
Surface emitter LED - ANS LED that emits light perpendicular to the semiconductor chip.
Most LEDs used in data communications are this type.
Step index fiber - ANS This is a multimode fiber where the core is all the same index of
refraction.
Steady State Modal Distribution - ANS Equilibrium modal distribution (EMD) in multimode
fiber (achieved some distance from the source) where the relative power in the modes
becomes stable with increasing distance.
Splitting Ratio - ANS The distribution of power among the output fibers of a coupler.
2 @COPYRIGHT 2025/2026
THRU Z EXAM 2025/2026 QUESTIONS
AND ANSWERS 100% PASS
Watts - ANS What is a linear measure of optical power?
Wavelength - ANS What is the measure of the color of light, usually expressed in
nanometeres (nm) or microns (*m)?
Wavelength Division Multiplexing (WDM) - ANS What do you call a technique of sending
signals of several different wavelengths of light into the fiber simultaneously?
Working Margin - ANS The difference (in dB) between the power budget and the loss budget
(i.e. the excess power margin) is known as what?
Visual Fault Locator (VFL) - ANS A device that couples visible light into the fiber to allow
visual tracing and testing of continuity.
Vertical Cavity Surface Emitting Laser (VCSEL) - ANS A type of laser that emits light vertically
out of the chip, not out of the edge, and is widely used in fast multimode networks.
Transmitter - ANS A device which includes an LED or laser source and signal conditioning
electronics that is used to inject a signal into fiber.
1 @COPYRIGHT 2025/2026
, Total internal reflection - ANS Confinement of light into the core of a fiber by the reflection
off the core-cladding boundary.
Test source - ANS A laser diode or LED used to inject an optical signal into fiber for testing
loss of the fiber or other components.
Test kit - ANS A kit of fiber optic instruments, incl. power meter, source and test accessories
(to measure loss and power)
Test cable - ANS A short single fiber jumper cable with connectors on both ends. This cable
must be made of fiber and connectors of matching type...
Termination - ANS The preparation of the end of a fiber to allow connection to another fiber
or active device.
Talkset - ANS A communication device that allows conversation over unused fibers.
Surface emitter LED - ANS LED that emits light perpendicular to the semiconductor chip.
Most LEDs used in data communications are this type.
Step index fiber - ANS This is a multimode fiber where the core is all the same index of
refraction.
Steady State Modal Distribution - ANS Equilibrium modal distribution (EMD) in multimode
fiber (achieved some distance from the source) where the relative power in the modes
becomes stable with increasing distance.
Splitting Ratio - ANS The distribution of power among the output fibers of a coupler.
2 @COPYRIGHT 2025/2026
