The glossary of FTTH--part 1

Adapter

A mechanical media termination device designed to align?and join fiber optic connectors often referred to as coupling,?bulkhead, or interconnect sleeve.

Angled Polish Connector (APC)

Connectors that have their end-face mating surface polished?at an 8-degree angle to the fiber axis. Minimizes reflections; required in RF video applications.

Armor

The additional protective element beneath the outer jacket provides?protection against severe outdoor environments. Usually made of plastic-coated steel, it may be corrugated for flexibility.

Attenuation

The decrease in a signal’s magnitude of power during #transmission between points. A term used for expressing the total loss of an optical system, normally measured in decibels (dB) at a specific wavelength.

Attenuation Coefficient

The rate of optical power loss with respect to distance along?the fiber, is usually measured in decibels per kilometer (dB/km) at a specific wavelength. The lower the number, the better?the fiber’s attenuation. Multimode wavelengths are 850 and 1300 nanometers (nm); single-mode #wavelengths are 1310?and 1550 nm. Note: When specifying the #attenuation, it is important to note whether the value is average or nominal.

Attenuation Test Set

Test set having a calibrated light source and meter; used to?measure the power loss in an optical link or network.

Bend-Improved Optical Fiber?

Class of single-mode optical fibers compatible with?ITU G.657.A recommendation and having bending?performance of 0.75 dB per 360-degree turn at 1550 nm?with a 10 mm bend radius. These fibers are required to be backward compatible with standard single-mode.

Bend-Insensitive Optical Fiber

Class of single-mode optical fibers with bending performance?of .1 dB per 360-degree turn at 1550 nm with a 5 mm bend radius.

Bend-Optimized Optical Fiber

Any single-mode fiber that has been engineered to provide?low loss at 1550 nm under tight bending conditions, when compared to standard single-mode fibers.

Bend-Tolerant Optical Fiber

Class of single-mode optical fibers compatible with ITU G.657.B?recommendations and having the bending performance of 0.5 dB per 360-degree turn at 1550 nm with a 7.5 mm bend radius.?These fibers are not required to be backward compatible with standard single-mode fibers.

Broadband Passive Optical Network (BPON)

The system is described in ITU G.983 standard. Uses optical splitters?to create a one-to-many relationship between the CO/HE and the subscribers. Capable of delivering voice and data; usually?combined with an RF overlay for video. Usually no active (powered) components between CO/HE and the subscriber.

Brownfield

Existing neighborhoods and/or MDUs are already served by at?least one provider.

Buffer Tube

Extruded cylindrical tube covering optical fiber(s) used for?protection and isolation.

Cable Assembly

Optical fiber cable that has connectors installed on one or?both ends. General use of these cable assemblies includes the interconnection of optical fiber cable systems and optoelectronic equipment. If connectors are attached to only one end of a cable, it is known as a pigtail. If connectors are?attached to both ends, it is known as a jumper or patch cord.

Cable Bend Radius

The minimum recommended bending radius during installation?or after installation so that cable damage will not occur. Cable bend radius during installation infers that the cable is?experiencing a tensile load. Free bend infers a smaller allowable bend radius since it is at a condition of the minimal load.

Central Member

The center component of a cable. It serves as an anti-buckling?element to resist temperature-induced stresses and sometimes serves as a strength element. The central member material is?normally dielectric, glass-reinforced plastic.

Central Office (CO)

The telephone company’s central location contains active?(powered) equipment, from which services are provided. May contain telephone switching equipment and/or optical line?terminals and RF video for BPON and GPON systems.

Cladding

The material surrounding the core of an optical waveguide.?The cladding must have a lower index of refraction to keep the light reflecting through the core.

Coating

Material is put on a fiber during the drawing process to protect?it from the environment and handling.

Conduit

Pipe or tubing through which cables can be pulled or housed.

Connecting Hardware

A device used to terminate an optical fiber cable with connectors and adapters that provide an administration point for cross-connecting between cabling segments or interconnecting to electronic equipment.

Connector

A mechanical device is used to align and join two fibers together to provide a means for attaching to and decoupling from a transmitter, receiver, or another fiber (patch panel). Commonly used connectors include the LC, SC, and ST compatible.

Connector Panel

A patch panel designed for use with fiber optic hardware; it contains either 6, 8, or 12 connector adapters pre-installed for use with field-installable or pre-connectorized termination methods.

Core

The central region of an optical fiber through which light propagates from the transmitter.

Dielectric

Nonmetallic and, therefore, nonconductive. Glass fibers are considered dielectric. A dielectric cable contains no metallic components.

Digital

A data format that uses different physical levels to transmit information corresponding to zeros and ones. A discrete or discontinuous signal.

Equipment Room (ER)

A centralized space for telecommunications equipment that?serves the occupants of a building. An equipment room is considered distinct from a telecommunications room because?of the nature or complexity of the equipment.

EPON

Ethernet Passive Optical Network

Fiber

An optical waveguide consisting of a core and cladding that?is capable of carrying information in the form of light signals.

Fiber Bend Radius

Radius fiber can bend before it risks breakage or an increase in attenuation.

Fiber Optics

Light transmission through optical fibers for communication or signaling.

Fiber to the x (FTTx)

Refers to a host of acronyms based on taking fiber to the home (#FTTH), node (FTTN), curb (FTTC), etc.

Gigabit Passive Optical Network (GPON)

Similar to BPON, but based on higher gigabit speeds. Like BPON, these systems may use an RF overlay for video, but because of their increased bandwidth per subscriber, are also being used for?IPTV deployment, in which all services (voice, video, and data) are placed on the #GPON and the RF video overlay is not required.

Gbps

Gigabits per second; 1 billion bits transmitted per second.

Greenfield

New construction of MDUs and neighborhoods. In this case, no service provider and no broadband network communications exist. The fiber cable system can be planned and placed efficiently while walls, ceilings, basements, and attics are openly accessible to create pathways.

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