GLOSSARY

Absorption

A physical mechanism in fibers that attenuates light by converting it into heat. In practice the temperature increase is very very small. Absorption is mainly from impurities such as the OH ion, and from defects in the glass crystaline structure.

Acceptance Angle
Half the vertex angle of the cone within which light may be successfully coupled into a multimode fiber. For graded index multimode fibers, the acceptance angle varies depending on the position on the end face of the fiber's core.

Angled End Face
A fiber whose end is deliberately polished at an angle to reduce reflections back into the LASER source.

Armor
A covering of steel tapes or wires applied over a cable sheath for additional protection. Used mostly on cables underwater or mining applications or whereever greater physical protection is needed.

Attenuation
The reduction in optical power as it passes through a fiber optic cabling system. In optical fibers, the power loss results from absorption and scattering and is generally expressed in decibels (dB) for a given length of fiber or per unit length (dB/km) at a specific wavelength.

Axial Ray
A ray that travels along the axis of an optical fiber.

Back Feed Pull
A method used to pull cable into conduit or duct systems when the cable is long or when placing cable into controlled environmental vaults, central offices, huts or under streets. With this method, the cable pays off its reel at an intermediate manhole and is first pulled in one direction. The remaining cable is then removed from the reel, laid on the ground, and then pulled in the opposite direction. Synonym for center pull.

Backscattering
The scattering of light in a direction opposite the original light source direction.

Bandwidth
Expressed in MHz, the modulating frequency of an optical source (LASER or LED) where the magnitude of the optical signal power is 3 dB lower than the power at no modulating frequency.

Barrier Layer
A layer of deposited glass whose purpose is to create a boundary against the diffusion of impurities into the core.

Bending Loss
Loss caused becuase light does not maintain total internal reflection due to the curvature in the fiber bend. See macrobending loss and microbending loss.

Binder
A helically applied colored thread, yarn, or plastic ribbon used to confine and sometimes separate and identify groups of fibers in a cable.

Blown Fiber
A method for installing fibers in which fibers are blown through tubes.

Boule
A porous preform used in fiber manufacture.

Breaking Strength
The amount of force needed to break a fiber.

Brittle
Easily broken without much bending.

Buffer Fiber
An protective acrylate/plastic coating applied over the fiber cladding.

Bundle
A group of fibers within a cable sharing a common binder group. For example, a group of fibers wrapped with a colorcoded tape in a cable or within a color coded plastic tube in a loose tube cable.

Capstan
A rotating drum or cylinder used for pulling cables by exerting traction upon a rope or pull line passing around the drum.

Center Pull
Cable is installed from a central point in the cable run. See backfeed pull.

Center Wavelength
The wavelength of an optical source that might be considered to be most powerful and dominant within the spectrum of wavelengths emitted and is typically in the middle or center of all parts of the emitted spectrum.

Chemical Vapor Deposition CVD
The general term used to describe MCVD, OVD, VAD and other preform manufacturing processes in which chemical vapors are deposited on the surface of a substrate in the presence of heat.

Chromatic Dispersion
This is mainly a problem with LASER systems. Although LASER's emit a single mode they still emit more than one wavelength within that mode. Thus the chroma or different wavelength will travel at different speeds causing a spreading of the pulse at the distant receiver. With very high speed switching at high data rates this spread becomes critical to error free operation.

Cladding
The glass layer having a low refractive index that surrounds a fiber's core. In single mode fibers, a portion of optical power travels in the cladding.

Cladding Diameter
The diameter of the circle that circumscribes the cladding layer.

Cladding Mode
A mode that can travel in the cladding when the cladding is surrounded by a medium having a lower index of refraction.

Cladding Mode Stripper
A device that causes cladding modes to escape from the fiber so that they do not adversely affect fiber measurements.

Cleaving
The controlled breaking of a fiber. Rough cleaving is used when making some connectors then the fiber is polished to create a smooth end surface. Precision cleaving breaks the fiber very precisely leaving a smooth end finish that is used in mechanical splices or fusion splices.

Closure
A cabinet, pedestal, or case used to enclose cable sheath openings necessary for splicing or terminating fiber cables.

Coating
A protective material (usually acrylate) applied to the fiber immediately after drawing to preserve its mechanical strength and cushion it from external forces that can induce microbending losses.

Coherent Light
The light emission has the same amplitude and is in phase. Lasers emit coherent light over a certain distance after which it becomes incoherent.

Composite Cable
Typically combinations of fiber and copper cables housed in a single sheathed cable. See hybrid cable.

Conduit
A tube or pipe that may be buried or installed within buildings for providing passageways into which cables can be pulled. Synonym for duct.(Panduit)

Connector
Hardware installed on fiber ends to provide physical and optical attachment of one fiber to another or to attach a fiber to an optical transmitter, receiver, or other component. Connectors are designed to be connected and disconnected from each other many times.

Consolidation
The preform is carefully melted to produce a solid cylinder of glass. See sinter.

Controlled Environmental Vault (CEV)
A below ground room that houses electronic and/or optical equipment under controlled temperature and humidity conditions.

Conventional Fiber
See dispersion unshifted fiber.

Core Diameter
The diameter of the circle that circumscribes the core.

Core Eccentricity
See concentricity error.

Core Fiber
The central region of an optical fiber having a higher index of refraction than the cladding and through which light is transmitted.

Core Non Circularity
A measure of the ovality of a fiber's core.

Core to Cladding Concentricity
See concentricity error.

Coupler, Connector (adaptor)
The connector component usually comprised of a sleeve and an external housing. It's used for mating two connectors to one another.

Critical Angle
The smallest angle at which a ray of light will be totally reflected within a fiber.

Crosstalk
The pickup of unwanted light from another fiber.

Cutback
A method for measuring the attenuation or band width of a fiber by first measuring the full length and then "cutting back" and remeasuring the fiber at a shorter length.

Decibel (dB)
A unit used to express the ratio of two powers and given by 10 log(P1/P2) It is used to measure the attenuation of fibers, splices and connectors and the return loss from these and other components.

Detector
A device that produces an electrical output signal when excited by an optical input signal. Photodetector.

Diagnostic Test
A test performed to learn more about the properties of a fiber. Usually made to improve product quality and increase production yield.

Dielectric Sheath or Cable
A sheath or cable that contains no electrically conducting materials such as metals. Dielectric cables are sometimes used in areas subject to high lightning or electromagnetic interference.

Dispersion Shifted Fiber
A singlemode fiber that has a nominal zero dispersion wavelength near 1550 nm.

Dispersion Unshifted Fiber
A singlemode fiber that has a nominal zero dispersion wavelength near 1310 nm. Synonym for conventional or unshifted fiber.

Distortion
An unwanted change in signal waveform.

Distribution Cable, inside plant
General purpose cables usually running horizontally from a closet on a given floor within a building. Distribution cables may be undercarpet, simplex, duplex, quad, or higher fiber count cables.

Distribution Cable, outside plant
Typically an underground or aerial cable, it may be armored, typically polyethelene sheathing for water protection. These cables are run outside between buildings.

Dopant
A material such as germanium, phosphorus or fluorine, added to silica to change its index of refraction.

Double Ended Closure
A splice closure with cable entry ports on both ends. These closures are suitable for both in line and butt splicing.

Double Pull
A method for pulling cable into conduit or duct liner that is similar to backfeed pulling except that it eliminates the need to lay the backfeed cable on the ground. The cable is simultaneously pulled at two locations.

Drawing
The manufacturing process by which fibers are pulled from preforms.

Drop Cable
A cable usually containing one or more fibers used to provide the final link between a distribution cable and a subscriber's premises. Synonym for service cable or lead in cable.

Dual Coat
A fiber coating structure consisting of a soft inner coating and a hard outer coating.

Duct
See conduit.

Ductility
The ability to be deformed and to retain the deformed shape.

Encapsulation
Encasing a splice or closure in a protective material to make it watertight.

End Finish
The quality of fiber's end surface commonly described as mirror, split, scratched, hackle, chipped, cracked, or by final polishing film size (30um, 5um, 1um, 0.03um), hand or factory finish, wet or dry polishing finish.

End Gap
The gap between two fibers which causes a loss between two fibers. The gap is caused by the joining hardware and termination method.

End to end loss
The optical loss of an installed fiber cable system. The loss consists of the loss of the fiber, splices and connectors from transmitter to receiver.

EPOXY
A combination of liquids that when mixed will solidify upon heat curing, ultraviolet light curing, or mixing with another accelerating liquid which chemically reacts with the original liquids. Epoxy is often used for setting fibers in connector ferules.

Extinction Ratio
The ratio of the power in the unexcited polarization mode to the power in the excited polarization mode at the output of a fiber. A measure of the polarization holding ability of a fiber.

Extrinsic Joint Loss
The optical loss caused by end separation, lateral offset and angular misalignments between two fibers at a joint.

Feeder Cable
The cable running from a central office to a remote terminal.

Ferrule
Typically a solid ceramic cylinder with a tiny hole through the middle of the cylindrical section where the fiber is fed through and fixed permanently with epoxy or adhesives.

Fiber
Hair thin silica glass structures, cylindrical in shape for transmitting photonic signals. They consist of a high index core surrounded by a lower index cladding and covered with a protective coating. Synonym for light guide. Spelling Fiber or Fiber is acceptable.

Fiber coating
See coating.

Fiber Dependent Test
A factory test specifically tailored to a particular fiber type.

Fiber Identifier
A test instrument that can differentiate between live and dead fibers in a working cable and can identify a preselected fiber to which a special transmitter has been attached.

Fiber Independent Test
A factory test performed on all fibers regardless of their type.

Fiber Optics
Light transmission through flexible optical fibers for communication or signaling.

Frequency
The number of cycles per unit of time, denoted by Hertz (Hz). One Hz equals one cycle per second.

Fresnel Reflection
The reflection of a portion of light from an optical discontinuity.

Fuse
To join two fibers together through heat melting.

Fusion Splice
Joining two fibers by applying localized heat sufficient to fuse or melt the ends of the two fibers together to form a continuous fiber.

Gas Pressurization
A method for preventing water from entering small openings in splice closures or cable sheaths by keeping the cables under pressure with dry gas.

Glass
A general term applied to about a thousand chemical formulations. Glasses are amorphous solids.

Graded Index Fiber
A type of fiber (multimode) where the refractive index starts at a high value in the center of the core and decreases smoothly with radius toward the cladding.

Group Delay
The transit time for a signal modulating a light source to travel a certain distance.

Group Velocity
The speed at which a signal modulating a light source travels through a fiber.

Hermetic Coating
A coating applied over the cladding of a fiber that retards the permeation of moisture into the fiber.

Hybrid Cable
A cable containing both optical fiber and electrical conductors. Synonym for composite cable.

Incident Angle
The angle between an incident ray and a line perpendicular to the end face of a fiber.

Incoherent Light
A random form of light whereby the phase of the light is unpredictable. LED’s emit incoherent light.

Index Dip
A decrease in the refractive index at the center of the core caused by some preform manufacturing techniques.

Index Matching Gel
A material, often a liquid, gel or epoxy whose refractive index is nearly equal to that of the fiber's core. Used to reduce the Fresnel reflections, refractive effects from a fiber end face. Also called elastomeric gel.

Index Profile
The refractive index of a fiber as a function of radius measurements from the cetral core to the outer cladding.

Index of Refraction
The ratio of light velocity in a vacuum to its velocity in a material medium. It is a function of wavelength and of the composition, temperature and pressure of the medium. Synonym for refractive index.

Infrared (IR)
The band of the electromagnetic spectrum having wavelengths between 1 and 100 microns.

Insertion Loss
The optical power loss caused by inserting an optical component such as a fiber, connector, or splice into an optical transmission path. Synonym for loss and optical loss.

Inside Plant
The portion of a cable network that resides inside buildings. Inside plant cables are usually shorter than 500 meters and are typically 100 meters long.

Interconnect Cabinet
Cabinets containing connector panels that interface between outside plant cables and patch/jumper cables leading to optoelectronic equipment. Used as access points for testing and rearranging outside plant fibers.

Interconnect Cable
Short distance cables intended for use within buildings primarily as patch cords, jumpers between equipment and generally less than 3 meters long.

Intermediate Assist
A method for Pulling cables into conduit or duct liner in which manual labor or machines are used to assist the pulling at intermediate manholes.

Intrinsic Joint Loss
The minimum optical loss that a joint can have. It is caused by dissimilarities in the geometry and optical properties of the two fibers being joined.

Ionizing Radiation
The form of electromagnetic radiation that can turn an atom into an ion by knocking one or more of its electrons loose. Examples are X rays, gamma rays and cosmic rays.

Jacket
A plastic extrusion over a fiber or cable.

Joint
The general term used to include both connectors and splices.

Laminate
A sheet of two dissimilar materials joined together.

LASER
Light Amplification by Stimulated Emission of Radiation. An optical source that emits coherent light with a narrow beam and narrow spectral width.

Lashing
Attachment of a cable to a support strand by wrapping steel wire or dielectric filament helically about them.

Lateral offset
Transverse misalignment of a source to fiber, fiber to fiber, or fiber to detector. Lateral offset causes an extrinsic loss that depends on the joining hardware and method.

Launch angle
The angle between an incoming light ray into a fiber and the fiber's axis.

Launching fiber
A fiber whose light output excites another fiber in a particular way.

LED (Light Emitting Diode)
A semiconductor optical source that emits incoherent light. LED’s emit light over wider angles and wider spectral widths than lasers.

Light
Traditionally, the region of the electromagnetic spectrum perceived by the human eyes. However, the term is used more generally in fiber optics to include wavelengths from about 0.3 to 30 um.

Local detection
A method for testing splices in which light is detected from the fiber immediately after the splice.

Local injection
A method for testing splices in which light is injected into the fiber immediately before the splice.

Long wavelength
Light whose wavelength is greater than about 1 um.

Loose construction
A type of cable construction in which the fibers are permitted to float freely to relieve stresses and minimize bending induced losses.

Loose tube
A loose cable construction in which a loose plastic tube is extruded around one to 12 fibers. Several tubes may then be stranded together to make a cable.

Loss
See insertion loss.

Macrobend
A large fiber bend that can be seen with the unaided eye.

Macrobending loss
The loss attributed to large bends in a fiber.

Manhole
An underground vault made from concrete or fiberglass, that is large enough for a person to enter and splice cables.

Material dispersion
One of the two components that causes chromatic dispersion. Material dispersion arises because the index of refraction of glass depends on the wavelength of light.

Mechanical Protection (MP)
An outer cable covering consisting of a corrugated steel tape plus an outer polyethylene jacket.

Mechanical splice
Any splicing method except fusion.

Mechanical stripping
Removing the coating from a fiber using a tool similar to those use for removing insulation from wires.

MessengerSee support strand.

Microbend
A small fiber bend that cannot be seen with the unaided eye. The bends are only a few micrometers high and have periods of a few milometers. They can occur due to coating, cabling, installation and temperature, etc.

Microbending loss
The loss attributed to microscopic bends in a fiber.

Microcracks
Submicroscopic flaws in the surface of glass fibers.

Modal bandwidth
A bandwidth limiting mechanism in multimode fibers (and also in "singlemode" fibers when operated at wavelengths below cutoff). Modal bandwidth arises because of the different arrival times of the various modes. Synonym for intermodal distortion.

Modal noise
Fluctuation in optical power because of the interaction of power traveling in more than one mode.

Mode
A discrete electromagnetic field pattern within a fiber. Only one mode propagates in a singlemode fiber whereas several hundred modes propagate in a multimode fiber.

Mode coupling
The exchange of power among modes. Synonym for mode mixing.

Mode Field Diameter (MFD)
A measure of the width of the guided optical power's intensity in a singlemode fiber. Synonym for spot size.

Mode filter
A device used to select, reject, or attenuate a certain mode or modes.

Mode mixer
See mode scrambler.

Mode mixer
See mode coupling.

Mode scrambler
A device used to couple power into all the modes of a fiber. Synonym for mode mixer.

Mode stripper
See cladding mode stripper.

Mode volume
The number of modes that a fiber is capable of guiding.

Modified Chemical Vapor Deposition (MCVD)
A process for manufacturing preforms by which glass layers are deposited on the inside surface of a starting tube.

Molecular hydrogen loss
The loss increase caused by the presence of hydrogen molecules. This loss increase is reversible if the hydrogen is permitted to escape.

Monochromatic
Consisting of one color or wavelength. Although light in practice is never perfectly monochromatic, it can display a narrow range of wavelengths.

Monomode fiber
See singlemode fiber.

Multifiber splice
Simultaneously splicing more than two fibers.

Multimode fiber
A fiber whose core diameter is large compared with the wavelength of light and therefore propagates more than one mode.

Noise
Any unwanted signal.

Nonionizing radiation
Electromagnetic radiation that does not turn an atom into an ion. Examples are visible light and radio waves.

Nonmetallic cable
See dielectric sheath or cable.

Numerical Aperture (NA)
An angle just outside the end face of a fiber that describes the largest angle that a light ray can have to the fiber axis and still be captured and propagate within the fiber.

Open
A broken fiber.

Optical cable assembly
A cable that is terminated with connectors. Usually the cable has been terminated by a manufacturer and is ready for installation.

Optical loss
See insertion loss.

Optical Time Domain Reflectometer (OTDR)
An instrument for characterizing a fiber. An optical pulse is sent down a fiber and the resulting backscattered light and reflected light back to the input is displayed as a function of distance on a screen. The instrument is useful for measuring fiber loss, splice loss and determining the location of faults or breaks.

Optoelectronic
A device that converts optical signals to electrical signals or vice versa.

Organizer, Splice Tray
A mechanical assembly consisting of a frame, one or more splice trays and mounting hardware.

Outside plant
The portion of a cable network that resides outside of buildings. Outside plant can consist of cable, conduit, utility poles, and enclosures.

Outside Vapor Deposition
(OVD)A process for manufacturing preforms by which layers of glass particles are deposited on the outside surface of a target rod.

Overfill launch
A condition for launching light into a fiber in which all the modes that the fiber can support are rated.

Overjacketing
See rod in tube.

Overlashing
Lashing a cable to a support strand that already supports another cable.

Passive splicing
Aligning the two ends of a fiber without monitoring its splice loss.

Pedestal
An above ground closure for splicing and terminating buried cables.

Photon
A discrete quantity of light energy.

Photon bucket fiber
A multimode fiber that captures all the light (photons) emitted by a transmitting singlemode fiber or multimode fiber. To capture all the light from a multimode fiber, the photon bucket fiber must have a numerical aperture and core diameter that is larger than that of the transmitting fiber. The connection to a photon bucket fiber has a low and reproducible loss.

Pigtall
A short length of fiber permanently attached to a component and use to couple light between it and another fiber.

Plenum cables
Cables used in the air return spaces above ceilings in buildings.

Plug, connector
The cylindrical or conical ferrule portion of a connector with the fiber fastened inside.

Polarization
The property of light relating to the direction of the vibrations. Light from the sun, incandescent lamps and many other sources vibrate in many directions perpendicular to the direction the light ray is traveling and is said to be randomly polarized. For lasers, the vibrations (all in a plane perpendicular to the light ray) are in a definite form that may be a straight line, circle, or ellipse.

Polarization maintaining fiber
A singlemode fiber that transmits light without changing its state of polarization. Synonym for polarization retaining fiber.

Polarization mode distortion (or dispersion)
Pulse spreading in a singlemode fiber because of the different group velocities for each of the two perpendicular polarizations of light traveling in the fiber.

Polarization retaining fiber
See polarization maintaining fiber.

Pole, utility
A tall slender column of wood, fiberglass, concrete, or steel used to support cables.

Polishing
Preparing a fiber end by moving the end over an abrasive material. (lapping film)

Polyethylene (PE)
A thermoplastic material formed by polymerizing ethylene gas. Used extensively in cables.

Polyimide
A solventbased polymer used as a coating for fibers that must withstand high temperatures.

Polyvinylchloride (PVC)
A thermoplastic material used in cables when fire retardant properties are required.

Preform
A glass structure that's a magnified version of the fiber to be drawn from it.

Primary coating
The first protective coating applied to the surface of a fiber in a dual coat structure.

Proof strain
The percentage increase in length that a fiber undergoes during proof testing.

Proof stress
The load divided by the fiber's crosssectional area that a fiber experiences during proof testing.

Proof testing
The application of force to a fiber to ensure that it has a minimum breaking strength.

Pulling eye
A device on the end of a cable to which a pulling line is attached for pulling cable into conduit or duct liner.

Pulse spreading
An increase in the width of an optical pulse as it travels along a fiber.

Qualification test
See design qualification test.

Quality assurance test
A test to verify that a product meets advertised performance specifications.

Quartz
A widely distributed mineral in nature that exists in crystalline form, for example as amethyst.

Rad
The unit used to measure the absorption of ionizing radiation.

Radiation
Energy and its propagation through matter or space. Radiation may either be "electromagnetic," which is usually considered to travel in the form of waves, or "particles" which is sub atomic particles moving at high speeds.

Ray
A geometrical representation of a light path through an optical medium that indicates the direction of energy flow.

Rayleigh scattering
Scattering of light caused by index of refraction variations in the submicroscopic structure of the glass.

Receiver
An optical and electronic package that takes optical input signals and converts them to electrical output signals.

Reel, cable
A large wooden or steel spool on which cable is wound for shipping and storage.

Reflectance
The ratio of reflected power to incident power. Synonym for "return loss."

Reflection
The abrupt change in direction of light as it travels from one material to a dissimilar material. Some of the reflected power in a fiber gets transmitted back to the source.

Refraction
The bending of light as it passes through two dissimilar materials or in a medium whose refractive index varies.

Refractive index
See index of refraction.

Regenerator
A receiver and transmitter combination used to reconstruct signals for digital transmission. The receiver converts incoming optical pulses to electrical pulses, decides whether the pulses are "1’s" or "0’s" generates "new" electrical pulses, and then converts them to "new" optical pulses for transmission on the fiber.

Repeater
An optoelectronic device that amplifies or boosts a signal. This is an analog technique, no regeneration takes place.

Restoration, cable
Locating, repairing and returning service to a damaged cable during an emergency.

Return loss
The reflectance measured at a point of reflection and then calculating the loss of that reflectance back to the source. This is important as too much reflectance may cause distortions in the transmitting device.

Ribbon
An assemblage of up to 12 fibers laid parallel to one another sidebyside and fastened together. Several ribbons can then be stacked on top of one another to make a cable.

Riser cable
High strength cables intended for use in vertical shafts between floors in a building.

Scattering
A physical mechanism in fibers that attenuates light by changing its direction.

Secondary coating
The protective coating applied over the fiber's primary coating in a dual coat structure.

Sheath, cable
The protective outer covering of a cable core. It may consist of plastics, metals and nonmetallic strength members.

Sheave
A grooved wheel or pulley used when installing cable in underground plant.

Shield, cable
The metallic components in a cable sheath that drain off the current induced by lightning discharges.

Shortpatch
An emergency cable restoration method in which a short length of cable is used to patch around the damaged region.

Short wavelength
Used to refer to light having wavelengths generally less than 1 um.

Silica
The short name for the chemical compound silicon dioxide (SiO₂) Silica exists in nature both in free form as in quartz and in combined form as in the silicates.

Silicate
A chemical compound of silicon, oxygen and metals.

Single end pull
A method for pulling cable into conduit or duct liner from one direction. The cable reel is positioned at a splicing manhole and a truck with a capstan winch is located at the pull manhole.

Singlemode fiber
A fiber having a small core diameter and in which only one mode (the fundamental mode which may consist of two polarizations) will propagate at the wavelengths of interest.

Sinter
The process of coalescing or uniting individual glassy particles into a continuous glassy layer. Synonym for consolidate.

Sleeve, connector
The critical tube or other hollow member used to align two connector plugs when making a connection. (adaptor)

Slotted core
A loose cable construction in which fibers are loosely placed into slots (grooves) molded around the out side surface of a plastic rod. Synonym for open channel and fluted.

Source
A device (usually LASER or LED) that emits light energy.

Speckle
The bright and dark spots on the end face of a fiber caused by the interference of modes. Do not look at the end of a fiber.

Spectral width
A measure of the wavelength content of optical power.

Splice
A connection of one or several fibers that in most instances is considered permanent.

Splice case
A metal or plastic housing used to enclose and protect fiber splices. Synonym for splice closure.

Splicingcutends
An emergency cable restoration method in which the cut ends are put back together.

Spool, fiber
The small reels or bobbins onto which fibers are wound during drawing and on which they are shipped.

Starting tube
The cylindrical silica glass hollow structure inside which glassy layers are deposited in the MCVD process.

Static fatigue
The decrease in fiber strength with time when under stress and exposed to humidity, high temperature, alkalinity or ammonia.

Static plow
A plow that rips open the ground with a plow share using brute force.

Stepindex fiber
A fiber having a uniform refractive index in its core and a sharp decrease in refractive index at the corecladding interface.

Storm loading
Characteristics of particular geographical areas such as ice buildup, wind speed and ambient temperature, that affect the design of aerial cable installations.

Strain
The length by which a wire or fiber deforms divided by its original length.

Stranding
The manufacturing process by which fibers are which fibers are wrapped about some other cable member. Stranding imparts extra length to the fibers.

Strength member
Steel aramid yarns, fiberglass epoxy, rods or other material used to increase the tensile strength of a cable.

Stress
The force per unit of crosssectional area.

Stripping
Removing the coating from a fiber

Support strand
A stranded metallic cable attached to utility poles and used to support aerial cables. The cables are lashed or clipped to the support strand.

Talk set, optical
An instrument for talking over fibers usually when installing and testing the cable.

Target rod
A solid cylinder usually made from alumina onto which submicroscopic glass particles are deposited in the OVD process.

Tensile strength
The pulling force necessary to break a material.

Tight construction
A type of cable construction in which the fibers are tightly coupled to other cable components and move with them.

Total bandwidth
The combined modal and chromatic bandwidth.

Total internal reflection
Confinement of light within a structure by having the light strike the interface between two optically different materials at an angle of incidence greater than the critical angle.

Transmitter
An optical and electronic package that takes electrical input signals and coverts them to optical output signals.

Tray, splicing
Flat rectangular compartments used to secure splices and store excess fiber.

Ultraviolet
The region of the electromagnetic spectrum containing wavelengths between 0.04 and 0.4 tan.

Underfill
A condition for launching light into a fiber in which not all the modes that the fiber can support are excited.

Underground
Cable installed in buried conduit. Does not include cables buried directly in the ground.

Universal closure
A splice closure suitable for use in aerial, underground or buried plant.

Vapor deposition
The process used for making preforms in which a chemical reaction of silicon vapors doped with other chemicals forms submicroscopic particles that deposit on the surface of a starting object.

Water peak
The increase in attenuation of a fiber near 1390 nm that occurs because of the hydroxyl (OH) ion impurity in the glass.

Waterproof cable
Cable containing a filling compound in all available spaces in the core to resist the entrance of water.

Waveguide
A conducting or dielectric structure able to support and propagate one or more modes.

Wavelength
The physical distance between two adjacent peaks or valleys in a sinusoidal wave. The property of light that determines its color.

Wavelength Division Multiplexing WDM
A method to simultaneously transmit two or more optical signals on a fiber by using different wavelengths.

Zero Fiber
a protective tube typically made of teflon used for protecting 250um buffer fiber after that fiber is exposed from an underground cable