Loss of signal power between points. In optical cables, attenuation
is a ratio of input power vs. output power, measured in decibels per
unit length, usually dB/km.
A factor expressing optical power loss per unit of length, expressed
A high-speed transmission system used to connect relatively distant
points. Backbone networks can be used to join autonomous networks
within buildings or between different buildings.
The information carrying capacity of a fiber. The bandwidth for a
given wavelength is the lowest frequency at which optical power has
decreased by 3 dB and is expressed in MHz•km.
The radius of curvature that an optical fiber cable can bend without
causing harmful effects on the optical or mechanical performance of
Different wavelengths travel along an optical medium at different
speeds. Wavelengths reach the end of the medium at different times,
causing the light pulse to spread. This chromatic dispersion is expressed
in picoseconds (of dispersion) per kilometer (of length) per nanometer
(of source bandwidth). It is the sum of material and waveguide dispersion.
The layer of material, usually glass, that immediately surrounds the
fiber core. The cladding is usually coated with another material to
provide protection when handling.
The process of cutting an optical fiber by a controlled fracture of
the glass, for the purpose of obtaining a fiber end, which is flat,
smooth, and perpendicular to the fiber axis. Coating A material applied
to the cladding for protective purposes.
In a wire or cable, the measurement of the location of the center
of the conductor with respect to the geometric center of the circular
The central part of the glass construction through which light is
A measure of the displacement of the center of the core relative to
the cladding center. Critical angle The smallest angle at which a
meridional ray may be totally reflected within a fiber at the core-cladding
The wavelength at which a singlemode fiber transmits a single mode
The standard unit used to express gain or loss of optical power. A
standard logarithmic unit for the ratio of two powers, voltages or
currents. In fiber optics, the ratio is power.
Nonmetallic. All-dielectric designs are inherently nonconductive;
all-dielectric cables contain no metal and are lightning resistant.
The cause of bandwidth limitations in a fiber. Dispersion causes a
broadening of input pulses along the length of the fiber. Two major
types are: mode dispersion caused by differential optical path lengths
in a multimode fiber and material dispersion caused by a differential
delay of various wavelengths of light in a waveguide material.
Electronic Industry Association.
Not all Ethernet and IEEE 802.3 standards are identical. In fact,
in some instances, there are enough differences in Ethernet standards
to cause major problems. In a network environment (such as Ethernet
Version 1.0 and IEEE 802.3) nodes can coexist and communicate properly
on a network but the important link is overall transceiver-to-node
Date Interface (FDDI)
An ANSI standard to ensure compatibility of components from different
Light transmission through optical fibers for communication or signaling.
The number of cycles per unit of time, denoted by Hertz (Hz). 1 Hertz
= 1 cycle per second.
A core refractive index profile that varies with the radius of the
Chemicals from the halogen family (chlorine, fluorine, bromine) are
typically compounded into plastic materials to improve the flame retardance.
When the materials are exposed to a high heat source, halogen gases
are released, limiting the spread of flames but potentially causing
a health hazard.
The unit of frequency, in cycles per second.
A thermoset jacket material providing excellent abrasion and flex
fatigue resistance; flame and oil resistance; and resistance to weather,
ozone, and oxidizing chemicals. Ideal for industrial and petrochemical
Total optical power loss caused by insertion of an optical component
such as a connector, splice, or coupler into a previously continuous
Services Digital Network)
ISDN is an international standard for transmitting digital information
(text, sound, voice, data, video, etc.)
Fiber optic cable that has connectors terminated on both ends.
The trademark of the Dupont Company for aramid yarn used as strength
Tensile strength in thousands of pounds per square inch.
Local Area Network.
A device that produces monochromatic, coherent light through stimulated
emission. Most lasers used in fiber optic communications are solid-state
A semiconductor device which emits incoherent light from a p-n junction.
A cable construction in which the optical fiber is placed in a plastic
tube having an inner diameter much larger than the fiber itself. The
loose tube isolates the fiber from the exterior mechanical forces
acting on the cushion. The space between the tube and the fiber is
often filled with a gel to cushion the fiber.
The total acceptable loss for a given system from transmitter to receiver.
Includes cables, splices and connectors.
Zero Halogen (LSZH)
Thermoplastic or thermoset jacketing compounds that emit limited smoke
and no halogens when exposed to high sources of heat.
Pulse dispersion due to the variations in a material's refractive
index as a function of wavelength.
In an optical fiber, all macroscopic deviations of the fiber's axis
from a straight line; distinguished from microbending.
Minute but severe bends in fiber that result in light displacement
and increased loss. Most microbending can be avoided by the correct
selection of materials and proper cabling, handling, and installation
A path of light through a fiber.
In singlemode fiber, the region in which the light transmitted is
larger than the glass core diameter. This mode field diameter is a
measured value and often listed as a requirement with core diameter
in fiber specifications.
A rubber elastomer jacket material providing excellent cold temperature
flexibility, abrasion resistance and flame retardance. Ideally suited
for outdoor, field deployable cables and repeated flexing applications.
A fiber optic cable that has a connector on only one end.
A cable whose flammability and smoke characteristics allow it to be
routed in a plenum area without being enclosed in a conduit.
Tough, chemical and moisture resistant jacketing material, ideal for
A jacketing material used mostly for outdoor cables. Provides excellent
abrasion resistance and low temperature flexibility.
Flame retardant jacketing material providing good mechanical protection,
flexibility, and abrasion resistance. Ideally suited for indoor cables.
The bending of a beam of light at an interface between two dissimilar
media or in a medium whose refractive index is a continuous function
of position (graded-index medium).
The ratio of the speed of light in a vacuum to the speed of light
in a material. Also called Index of Refraction.
Indoor cables made especially for between floor applications.
An optical fiber that supports only one mode of light propagation
above the cutoff wavelength.
A refractive index profile characterized by a uniform refractive index
within the core and a sharp decrease at the core-cladding interface.
That part of a fiber optic cable composed of aramid yarn, steel strands,
or fiberglass filaments that increase the tensile strength of the
A plastic jacketing material that softens when heated and becomes
firm on cooling. Thermoplastics include PVC, PE, Polyurethane, and
A jacketing material where the molecules have been cross-linked (interlocked)
through exposure to heat or irradiation. Once the material is "set,"
it cannot be softened or melted by re-heating. Thermosets include
Neoprene and Hypalon.
In tight buffer constructions the thermoplastic is extruded directly
over the coated fiber, increasing the outside diameter to 900 micron
(0.9 mm), an industry standard.
Dispersion caused by the fact that light travels at different speeds
in the core and cladding of singlemode fibers.
Wavelength In singlemode fibers, the wavelength at which the effects
of chromatic dispersion and waveguide dispersion are lowest; thus
providing the greatest information carrying capacity.