GLOSSARY OF BASIC FIBER TERMINOLOGY

Aerial
A type of fiber optic cable that is designed for hanging from a pole or supporting wire.

APC - Angled Physical Contact
Connector with an angled tip. The angled tip helps reduce insertion loss.

Armored
Fiber optic cables built with a protective structure around the outside. Armor is usually metal, and protects the cable from burrowing rodents and other threats.

Buffer
A layer which surrounds the cladding of a fiber, and provides some measure of physical protection. The buffer is typically made of a plastic material.

Burial
A type of fiber optic cable that is designed for burial directly in the earth. Burial cable is typically armored to protect it against rodents, and also built with moisture-resistant properties to protect against water intrusion.

Cladding
The layer which surrounds the core of a fiber. The cladding is slightly less transparent than the core, and reflects light back in to the core.

Connector
The structure at the end of a fiber optic cable that allows connection to a fiber port on a patch panel or electronic device.

Core
The transparent center of a fiber optic cable, where light is internally transmitted.

dB
Abbreviation for decibel, the unit of measurement for optical power in a fiber optic cabling system.

Duplex
A fiber optic patch cord with two connectors at each end, zip-corded together.

Ferrule
A round part of a connector that holds the fiber in place for polishing.

Fiber (or, optical fiber)
The glass construction of a fiber optic cable, consisting of the core, cladding, and buffer.

GBIC
Gigabit Interface Converter (pronounced "JEE-bic"). A transceiver device that plugs into a switch or other network device in order to provide a high-speed fiber optic interface.

Laser-Optimized Multi-Mode Fiber (LOMMF)
Multi-mode optical fiber that is designed for use with VCSEL lasers. Normally has an aqua-colored jacket; also known as OM3.

Multimode
A fiber cable that transmits more than one mode, or paths, of light to travel down the core. May come in two standard core sizes — 62.5/125 (OM1) or 50/125 (OM2).

Insertion Loss
The loss (in dB) from inserting a component such as a connector or coupler into a fiber optic signal path.

Loss Budget
The total amount of allowed loss, in dB, in a given fiber optic installation. Loss may be due to insertion loss because of connectorization, attenuation because of cable length, splicing of cable runs, and other factors.

Messenger
A parabolic structure that is added to an aerial fiber optic cable in order to help hang it to a pole or supporting wire.

OFNP
Optical Fiber Nonconductive Plenum. Plenum-jacketed fiber optic cables.

OFNR
Optical Fiber Nonconductive Riser. Riser-rated (usually PVC) fiber optic cables.

OTDR — Optical Time-domain Reflectometer.
A device used to locate faults in fiber optic cable installations.

Polish
The type of finish used on a connector.

Return Loss
The loss of signal power caused by a reflection.

Simplex
A fiber optic patch cord with a single connector at each end.

Single-mode
Supports only one mode of light propogation above the cutoff wavelength.

VCSEL-Vertical Cavity Surface Emitting Laser
A type of launch laser used on network electronic devices that are designed for use with LOMMF/OM3 fiber. VCSELs (pronounced "vixel") are a low-cost, low-power consumption laser.

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