FOA CFOT Terms and Definitions A
thru Z Questions with Detailed
Verified Answers
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.
Total internal reflection Ans: Confinement of light into the core of
a fiber by the reflection off the core-cladding boundary.
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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.