Elenco Fiber Optics Voice and Data Kit - Manual (Page 22)

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GLOSSARY 11
ABSORPTION Loss of power in an optical fiber,
resulting from conversion of
optical power into heat and
caused principally by impurities,
such as transition metals and
hydroxyl ions, and also
exposure to nuclear radiation.
ANGLE OF INCIDENCE Angle between the incident ray
and the normal.
ANGLE OF REFRACTION Angle between the refracted ray
and the normal.
ATTENUATION A general term indicating a
decrease in power from one
point to another. In optical fibers,
it is measured in decibels per
kilometer at a specified wave-
length.
BANDWIDTH A range of frequencies.
CABLE A fiber covered by a protective
jacket.
CAPACITOR A capacitor stores electrical
energy when charged by a DC
source. It can pass alternating
current (AC) but blocks direct
current (DC) except for a very
short charging current, called
transient current.
CLADDING The outer concentric layer that
surrounds the core and has a
lower index of refraction.
CONNECTOR A connector is a device which is
used to connect both ends of
the fiber to the source and
detector.
CORE The central, light-carrying part
of an optical fiber; it has an
index of refraction higher than
the surrounding cladding.
dB Decibel.
DECIBEL A standard logarithmic unit for
the ratio of two powers, voltages
or currents. In fiber optics, the
ratio is power. dB = 10 log
10
(P
1
/P
2
)
ELECTROMAGNETIC Any electrical or electro-
INTERFERENCE magnetic energy that causes
undesirable response, degrad-
ation, or failure in electronic
equipment. Optical fibers
neither emit nor receive EMI.
EMI Electromagnetic interference.
FIBER A light-carrying conductor made
up of glass or plastic.
INDEX OF REFRACTION The ratio of the velocity of light
in free space to the velocity of
light in a given material.
Symbolized by n.
INTERFACE Surface that separates two
materials.
LED Light-emitting diode.
LIGHT Electromagnetic radiation which
is visible to the human eye.
LIGHT EMITTING DIODE A semiconductor diode that
spontaneously emits light from
the PN junction when forward
current is applied.
NORMAL An imaginary line perpendicular
to the interface of two materials.
OP AMP A semiconductor device which
is used to amplify current,
voltage, or power.
PHOTON A photon of electromagnetic
energy. A “particle” of light.
PHOTO-TRANSISTOR A transistor that detects light.
PLASTIC FIBER An optical fiber having a plastic
core and plastic coating.
PC BOARD Its full name is printed circuit
board. It is a conductive pattern
glued to one or both sides of an
insulating material. Holes are
punched or drilled through the
conductor and board to allow
the interconnection of electronic
parts.
PRISM A device which splits white light
into a rainbow of colors.
SOURCE The light emitter, either an LED
or a laser diode in a fiber optic
link.
WAVELENGTH The distance between the same
two points on adjacent waves.
11 The “GLOSSARY” Section is reproduced by permission TECHNICIAN’S GUIDE TO FIBER OPTICS 2E (PAGES 256-264)
By Donald J Sterling, Jr. - DELMAR PUBLISHERS, INC., Albany, New York, Copyright 1993