FOA CFOS/W key terms

The service-provider endpoint of a PON that sits in the central office or headend, aggregates subscriber traffic, manages ONTs, and drives the downstream and upstream optical signals on each PON port.

The subscriber-side device that terminates the PON fiber, converts between optical and electrical signals, and delivers Ethernet or voice services to the customer's premises equipment.

A single-subscriber ONU, usually mounted at the home, that converts the PON optical signal into the customer's service interfaces such as Ethernet, Wi-Fi, and analog phone ports.

A point-to-multipoint fiber architecture in which unpowered splitters fan one feeder fiber out to many subscribers, sharing the OLT port's bandwidth and reducing outside-plant electronics.

An ITU-T PON standard using 2.488 Gbit/s downstream and 1.244 Gbit/s upstream with fixed-length GTC frames, supporting up to 128 splits and multiple service types over one fiber.

Symmetric 10 Gbit/s PON standard (ITU-T G.9807.1) that can coexist with GPON on the same outside plant by using a different downstream wavelength, easing upgrades without re-splicing the ODN.

The passive portion of a PON between the OLT and the ONTs, comprising feeder, distribution, and drop cables plus splitters, connectors, and closures that together define the optical loss.

The high-fiber-count cable running from the central office to the first splitting or distribution point, carrying all subscribers' traffic on shared fibers before any branching occurs.

The cable segment between the splitter or distribution hub and the access points near subscribers, typically with fewer fibers than the feeder and routed through pedestals or closures.

The final short cable from an access terminal, closure, or splitter port to the subscriber premises, often a small-diameter or ruggedized single-fiber cable designed for aerial or buried routing.

A cabinet or enclosure where feeder fibers are spliced to splitters and distribution fibers, providing cross-connect, splitting, and test access points in the outside plant.

A passive component that divides one optical input among several outputs, commonly in 1x2, 1x4, 1x8, 1x16, or 1x32 ratios, each stage adding insertion loss to the optical budget.

The optical power lost when a component such as a connector, splice, or splitter is inserted into a link, expressed in decibels as the ratio of output to input power.

A measure in decibels of how much optical power is reflected back toward the source at a connector, splice, or fiber end, with higher values indicating cleaner, better-matched terminations.

The allowable optical loss between transmitter and receiver, calculated from launch power minus receiver sensitivity, which must exceed total fiber, splice, connector, and splitter losses.

The measured or calculated total attenuation of a complete fiber path from OLT to ONT, including cable attenuation, splice loss, connector loss, and splitter loss.

A test instrument that launches light pulses into a fiber and graphs backscatter and reflections versus distance, revealing splice and connector loss, breaks, bends, and overall link attenuation.

The minimum fiber distance after a reflective event over which an OTDR can still detect and measure a following event, shortened by narrower pulses but traded against dynamic range.

The distance after a reflective event over which an OTDR can accurately measure loss of a subsequent non-reflective event, a key specification when testing closely spaced splices or connectors.

A calibrated instrument that reads absolute or relative optical power at a given wavelength, used to verify transmitter output and receiver input levels during activation and troubleshooting.

A paired light source and power meter used to measure end-to-end insertion loss of a fiber link at one or more wavelengths, typically following a reference or one-jumper method.

A stabilized laser or LED transmitter emitting at a defined wavelength, such as 1310, 1490, or 1550 nm, paired with a power meter for loss testing.

Joining two fibers permanently by aligning and fusing their cleaved ends with an electric arc, producing a low-loss, low-reflection joint protected by a splice protector sleeve.

A field-installable device that aligns and holds two cleaved fibers together, often with index-matching gel, giving a quick but generally higher-loss joint than fusion splicing.

The optical attenuation contributed by a splice, typically a few tenths of a decibel for fusion splices, caused by core misalignment, end quality, or mode-field mismatch.

Scoring and breaking a fiber to produce a flat, perpendicular end face within a tight angle tolerance, a prerequisite for low-loss splicing and reliable connector termination.

The end-face geometry of a fiber connector, such as PC, UPC, or APC, where APC's angled, typically green, ferrule reduces back-reflection and must not be mated with flat-polish connectors.

A push-pull square-bodied fiber connector with a 2.5 mm ferrule, widely used on PON ports, splitters, and ONTs because it latches securely and is easy to field-mate.

A small-form-factor connector with a 1.25 mm ferrule and latch, common on high-density patch panels and equipment ports where space and port count matter.

Single-mode fiber designed with a depressed cladding or trench to confine light tightly, allowing tight cable bends at drop and in-home routing without excessive macrobend loss.

Radiated loss caused by bending fiber beyond its minimum bend radius, showing up as increased attenuation at longer wavelengths and often as a distinct loss event on an OTDR trace.

Combining multiple optical signals at different wavelengths onto one fiber, used in FTTH to carry separate services or to overlay GPON and XGS-PON traffic on shared outside plant.

Stringing fiber cable on poles, using strand, lashed or ADSS cable, with attention to sag, clearance, and messenger attachment so the cable is not over-tensioned or abraded.

The tightest curvature a cable or fiber may be subjected to without damage or excess loss, usually stated as a multiple of cable diameter and enforced during pulling and storage.

The boundary where the provider's outside-plant responsibility ends and the customer's premises wiring begins, commonly at the ONT or an external enclosure and important for fault isolation.

A rack- or wall-mounted assembly of adapter ports that terminates incoming fibers and allows flexible cross-connection via patch cords, simplifying moves, adds, and testing.

A short factory-terminated fiber with a connector on one end and bare fiber on the other, fusion spliced to a cable fiber to provide a reliable connectorized end.

A single optical interface on the OLT serving one PON branch, with a defined split ratio and power budget; its count and split sizing drive the network's subscriber capacity.