Fiber Optic Glossary of Terminology

Attenuator - A device which lowers the strength of an optical signal.

Bend Loss - Signal attenuation in a fiber cable due to being bent around too great an angle.

Cladding - The sheathing material which surrounds the core of an optical fiber in order to keep the light from escaping.

Connector Loss - Optical loss at connection points in fiber cables.

Endoscope - A fiber scope designed to be inserted into the body to faciliate inspection during diagnostic and surgical procedures. They are used in conjunction with light sources.

Fault Locator - A device used to to locate breaks, bends, bad connections, splices and other causes of optical loss in fiber cabling. One example of a fault locator is an OTDR.

Fiber Certifier - A device which measures optical loss and compares the test results to industry standards. A fiber certifier can also measure the overall cable length. A fiber certifier provides a much more automated testing process compared to an OLTS or OTDR.

Fiber Cleaver - A precision device used in the process of cutting or cleaving a fiber optic cable in order to leave the end perfectly flat and smooth. When splicing fiber cables together the cable ends must be perfectly flat so as to mate together perfectly.

Fiber Optic Cable - A cable containing many optical fibers which is coated with a transparent cladding. Fiber optic cabling is used extensively in the telecommunications industry to transmit data as it possesses a greatly increased bandwidth compared to metal cable. This allows it transmit much more data. It has the added benefit of being much less susceptible to interference when compared to metal cable.

Fiber Optic Receiver - An instrument that converts light into electrical signals.

Fiber Optic Transmitter - A device which converts an electrical signal into light and injects it into a fiberoptic cable.

Fiberscope - A device consisting of a flexible fiber bundle, a lens and an eyepiece. A fiberscope is used to peer into otherwise inaccessible areas.

FTTb - Stands for "fiber to the building". This refers to fiber optic cable coming from an ISP to a physical building.

FTTc - Short for "fiber to the curb".

FTTd - Short for "fiber to the desk".

FTTh - Short for "fiber to the home".

FTTp - Short for "fiber to the premises".

FTTx - Short for "fiber to the x". "x" can stand for anything such as business, curb, home, premises, desk, etc.

Fusion Splicer - A device which splices optical fibers together by fusing or melting them, most often by using an electrical arc. See "Fusion Splicing" for a more in-depth explanation of how the fiber fusion splicing process works.

Jacket - The protective outer coating or sheath of a fiber cable.

Lightguide - A fiberoptic cable or bundle of fiber cables.

Light Source - A source of light that is used in conjunction with endoscopes and borescopes. Light sources are typically laser, LED or halogen.

Mass Fusion Splicer - A fusion splicer which can splice multiple fibers in a ribbon fiber cable simultaneously. See "Fusion Splicing" for more information on the fiber fusion splicing process.

Nanometer (nm) - The unit of measurement used to measure the wavelength of light. A nanometer is equal to one billionth of a meter.

Optical Fiber - A type of fiber made of glass or plastic which is designed to allow light to travel along its length.

Optical Loss - Optical power which is lost as the light is transmitted through fiber, couplers, splices, and other optical equipment.

Optical Loss Test Set (OLTS) - A device which is used to measure the quantity of optical loss in fiber cables. An optical loss test set consists of a meter and a light source.

Optical Time Domain Reflectometer - An OTDR is a device used to find faults, bends and splices in fiber optic cabling. See "How OTDRs Work" for an in-depth explanation of how an OTDR works.

Power Meter - A device which measures the power of a light beam.

SDH - Short for Synchronous Digital Hierarchy, a multiplexing protocol for transferring multiple digital bit streams using lasers or light-emitting diodes over the same optical fiber.

SONET - Short for Synchronous Optical Networking, a multiplexing protocol for transferring multiple digital bit streams using lasers or light-emitting diodes over the same optical fiber.

Spectrum Analyzer - A spectrum analyzer (also sometimes referred to as a spectral analyzer) measures an optical or electrical waveform and displays the frequency response curve in real time.

Splice Loss - Optical power lost at a splice point.

Wavelength - A measurement of the color of light which is expressed in nanometers (nm).

WDM - Short for wavelength-division multiplexing, a technology where multiple optical signals are multiplexed on a single optical fiber by utilizing a different wavelength of light for each signal.