Homes Connected

Number of residential and business premises to which a service provider is supplying FTTH services under a commercial contract.

Homes Passed

Number of residential and business premises to which a service provider has access to deliver FTTH services within the standard service activation period (for example 30 days) should the owners/occupiers sign a contract for an access service.

Horizontal Cross-Connect (HC)

A cross-connect of horizontal cabling to other cabling, e.g., horizontal, backbone, equipment.

Index of Refraction

The ratio of light velocity in a vacuum to its velocity in a given transmission medium.

Internet

Refers to use of the Public Internet for exchanging email, Web-browsing, video gaming, etc.

Jumper

Optical fiber cable that has connectors installed on both ends.

Laser

Term originated as an acronym for “light amplification by stimulated emission of radiation.” An opto-electronic device that produces coherent light with a narrow range of wavelengths, typically centered around 850, 1310, or 1550 nm. Lasers with wavelengths centered around 850 nm are commonly referred to as VCSEL.

Link

A telecommunications circuit between any two telecommunications devices, excluding the equipment connectors.

Mechanical Splicing

Joining two fibers together by permanent or temporary mechanical means (vs. fusion splicing or connectors) to enable a continuous signal.

Medium Density Polyethylene (MDPE)

A type of plastic material used to make cable jackets.

Microduct

Small duct, usually < 1/2 in (13 mm), installed in MDUs to protect single-fiber drop cables. It also makes it possible to easily remove/replace drops in the event of damage. Microduct typically has a total installed cost greater than the placement of rugged drop cables directly into building structures.

Mode

A term used to describe an independent light path through a fiber, as in multimode or single-mode.

Mode Field Diameter (MFD)

The functional parameter for defining the diameter of the light-guiding region (i.e., the core and cladding) of a single-mode fiber.

Modulation

Coding of information onto the carrier frequency. This includes amplitude, frequency, or phase modulation techniques.

Multi-dwelling Unit (MDU)

A building structure that has two or more residential dwelling units occupied by separate entities. The living units may be owned individually or the entire building may be owned as one property with units rented to tenants.

Multiplex

Combining two or more signals into a single transmission path that can be individually recovered at the receiving end.

Optical Line Terminal (OLT)

For BPON and GPON systems, these is the electronics located in the CO/HE and which control the ONTs served at each subscriber’s location. Typically, OLTs service 16, 32, or 64 ONTs.

Optical Network Terminal (ONT)

For BPON and GPON systems, these is the electronics located at the subscriber’s premises. The ONT converts the optical signal to copper and coax-based signals for connection to phones, computers, and televisions in residence.

Optical Time Domain Reflectometer (OTDR)

A test set that sends out light and senses light scattered and reflected back to the set. It is capable of showing the distance to faults and other “events” in an optical cable, as well as the attenuation (power loss) associated with each event.

Outside Plant (OSP)

Cabling outside of buildings, including aerial and buried installations.

Patch Cord

A fiber optic interconnect or cross-connect jumper.

Patch Panel

A length of optical cable with a plug on one or both ends.

PC

Physical contact of two terminated fiber strands.

Pigtail

Optical fiber cable that has a connector installed on one end.

Point-to-Multipoint (P2MP)

The cable plant provides branching optical paths from the telecommunications operators switching equipment to more than one contiguous location such that portions of the optical paths are shared by traffic to and from multiple locations. In generic terms, this is a tree-and-branch topology.

Point-to-Point (P2P)

The cable plant provides optical paths from the telecommunications operator’s switching equipment to a single contiguous location such that the optical paths are dedicated to traffic to and from this single location. In generic terms, this is a star topology.

PE

Polyethylene is typically used for outdoor cable jackets.

Preconnectorized

Cables have optical connectors pre-installed and tested at a factory before being shipped to the field for installation as an assembly.

Receiver

An electronic package that converts optical signals to electrical signals.

Reflectance

Reflectance is the ratio of power reflected to the incident power at a connector junction or other component or device, usually measured in decibels or dB. Reflectance is stated as a negative value, e.g., -30 dB. A connector that has a better reflectance performance would be a -40 dB connector or a value less than -30 dB. The terms return loss, back reflection, and reflectivity are also used synonymously in the industry to describe device reflections but are stated as positive values.

Residential

Refers to private users in their homes. Residential users may live in either a multi-dwelling unit (MDU), such as an apartment/condominium or in a single-family dwelling unit (SFU), such as a stand-alone house/villa/landed property.

Riser

Pathways in a building that go from floor to floor. Cables and nonmetallic ducts must be “riser rated” to control flame propagation building in this space. The exception, depending on local codes, is for cables placed in sealed metallic ducts/conduits.

Single-Mode (SM) Fiber

An optical waveguide (or fiber) in which the signal travels in one mode. The fiber has a small core diameter, typically 8.3 to 9.5 μm.

Splice Closure

A container used to organize and protect splice trays and splices. Typically used in outside plant environments.

Splice Tray

A container is used to secure, organize, and protect spliced fibers.

Splicing

The permanent joining of a bare fiber end to another fiber, either one pair at a time or in a mass.

Splitter (Optical)

An optical device which splits the optical power of one signal into multiple outputs, each containing the same signal but at a lower power level. For BPON and GPON systems, splits of 1×2 to 1×64 are used.

Tight-Buffered Cable

Type of cable construction whereby each glass fiber is tightly buffered by a protective thermoplastic coating to a diameter of 900 micrometers/micron (μm). Increased buffering provides ease of handling and connectorization.

Triple-Play Services

The offering, by carriers, of voice, video, and data services over one medium (one network). Usually, this reduces network complexity and cost for the carrier and offers preferred pricing for subscribers.

Ultra Physical Contact (UPC) Connector

An optical connector whose end face has been radiused and polished to minimize reflections. Unlike the angled polish connector (APC), the mating surfaces are NOT angled to the axis of the fiber. APCs provide superior reflectance performance compared to UPCs.

UV

Ultraviolet

Video

Refers to the exchange of visual material by use of IP, RF (carried via a separate optical wavelength), or other encoding and transport protocols.

VFL

Visual fault locator

Voice

Refers to the exchange of human conversations by use of IP or other encoding and transport protocols.

Wavelength

The distance between two successive points of an electromagnetic waveform, is usually measured in nanometers (nm).

Wavelength Division Multiplexer (WDM)

A passive device is used to combine and/or separate optical signals of different wavelengths. Example: WDMs combine the downstream data/voice signals (1490 nm) with RF video signals (1550 nm) in the CO to be sent out toward subscribers.

Zero Dispersion Wavelength

Wavelength at which the chromatic dispersion of an optical fiber is zero. Occurs when waveguide dispersion cancels out material dispersion, around 1310 nm for standard single-mode fiber.