Punjab PSEB Matric NSQF Telecom (Optical Fiber Splicer) key terms

The bouncing of light back inside a medium when it strikes the boundary with a lower-refractive-index material at an angle steeper than the critical angle; this effect keeps light guided along the fiber core.

The smallest angle of incidence, measured from the normal, at which light striking the core-cladding boundary is totally reflected instead of passing out of the core.

A number describing how much light a fiber can accept, equal to the sine of the largest acceptance angle; higher values suit short links, lower values suit single-mode long-haul work.

A fiber in which the refractive index jumps sharply from core to cladding, giving simple construction and higher modal dispersion, typically used for multimode short-distance links.

A multimode fiber whose refractive index falls gradually from the core centre outward, reducing modal dispersion so faster signals travel farther than in step-index multimode fiber.

A fiber with a very small core, about 8 to 10 micrometres, carrying one propagation path; it offers the lowest attenuation and dispersion for long-distance and backbone networks.

A fiber with a larger core, commonly 50 or 62.5 micrometres, allowing many light paths; cheaper to connectorise and used mainly inside buildings and data centres.

The loss of optical power as light travels along fiber, caused by absorption and scattering and measured in decibels per kilometre; it limits how far a signal can reach.

A logarithmic unit expressing the ratio of two power levels; in fiber work it describes loss, gain and signal margin, and a 3 dB change means the power has halved or doubled.

Pulse spreading in multimode fiber because different light paths arrive at slightly different times; it narrows bandwidth and grows worse as the link gets longer.

Pulse spreading because different wavelengths travel at slightly different speeds in the fiber; it matters most for high bit rates over long single-mode spans.

A band of light wavelengths where fiber attenuation is low and equipment is standardised, notably 850, 1300 and 1310 nanometres and the 1550 nanometre band.

A cable design in which fibers sit loosely inside gel-filled or dry tubes that are stranded around a central strength member, protecting fibers from strain and moisture in outdoor routes.

A cable where each fiber has a direct plastic coating, giving a small flexible cord for patch leads and indoor risers, but with less protection from pulling and temperature extremes.

A strong synthetic yarn laid inside cables to carry tensile load and stop the fiber from stretching when the cable is pulled through ducts or trays.

A central or embedded element, such as steel wire, FRP rod or yarn, that takes pulling and bending loads so the glass fibers themselves carry almost no tension.

The standard sequence of twelve colours, blue, orange, green, brown, slate, white, red, black, yellow, violet, rose and aqua, used to identify individual fibers and tube positions in a cable.

The protective plastic tube, usually 250 micrometre fiber inside, that encloses one or more fibers and carries the colour marking used to locate a particular fiber during splicing.

The practice of reading cable print legends, tube colours and fiber colours to confirm exactly which strand is being worked on, preventing wrong-fiber splices and outages.

A field instrument that aligns two cleaved fiber ends and fuses them with an electric arc, producing a permanent low-loss joint; it also estimates splice loss and displays the result.

A precision tool that scores and snaps the fiber to create a flat, perpendicular end face; a good cleave angle is essential for a low-loss splice.

The deviation of a cleaved fiber end from a perfect right angle, usually measured in degrees; large angles cause air gaps, bubbles and high splice loss.

A hand tool with sized blades or a thermal stripper that removes the outer jacket and buffer coating without nicking the glass cladding beneath.

A visible red laser source used to check continuity, find sharp bends and breaks, and confirm which fiber is which; light escaping at a fault shows as a bright glow.

A test instrument that sends short light pulses into fiber and plots reflections against distance, revealing splice loss, connector loss, breaks and overall link length.

A meter that measures received optical power in decibel-milliwatts or microwatts, used for loss testing with a light source and for checking transmitter output at an ONT or OLT.

The maximum total loss a link may have and still work, calculated from transmitter power, receiver sensitivity and margin, then compared with measured or calculated losses.

The optical power lost at a joint between two fibers, expressed in decibels; good fusion splices are typically below 0.1 dB and are checked by the splicer or an OTDR.

The total loss added by a component or joint, measured as the difference between input and output power; for connectors it includes alignment and end-face quality effects.

A permanent joint made by aligning cleaved fibers and melting their ends with an electric arc; it gives the lowest loss and best long-term reliability for network joints.

A joint that holds two cleaved fibers in precise alignment with a small ferrule or V-groove and index-matching gel, needing no power but usually showing higher loss.

A clear gel with a refractive index close to glass, placed at a joint or connector to remove the air gap so light passes through with minimal reflection and loss.

The polished or cleaved surface at the end of a fiber or connector; it must be clean, scratch-free and correctly shaped, or loss and reflections rise sharply.

A magnifying instrument, often with a screen, used to examine connector and fiber end faces for dirt, cracks, scratches and polish defects before mating or splicing.

A sealed housing that protects spliced fibers and trays from water, dust and mechanical damage, used in buried, aerial and duct joints and often filled with encapsulant.

A shallow tray inside a closure that holds spliced fibers in curved channels, keeps them at a safe bend radius and organises the joints for later re-entry.

The minimum safe curve radius for fiber or cable, commonly ten times the cable diameter during installation; tighter bends leak light and can crack the glass.

Extra attenuation caused by bending fiber more sharply than its design allows, which pushes light out of the core; it is worst at long wavelengths and often shows on an OTDR.

A passive optical network that shares one feeder fiber among many users through unpowered splitters, carrying traffic between an OLT at the exchange and ONTs at customer premises.

The optical line terminal at the network operator's site; it drives the PON, manages ONTs and connects the access network to the wider transport and core network.

The optical network terminal at the subscriber's premises; it terminates the PON fiber, converts optical signals to electrical services and is the point where technicians often measure receive power.

A passive optical coupler that divides one input among several outputs, such as 1:8 or 1:32, adding loss that must be counted in the PON loss budget.

A short length of fiber permanently terminated at one end and bare at the other, fusion spliced to a cable fiber so the link can be connected to patch panels.

Light reflected back at a boundary between two media of different refractive index, such as glass and air; it causes return loss and weakens the forward signal.

The zero-loss reading taken by holding the launch lead and meter together before testing; subtracting it from later readings gives the true link loss.

The short length after a reflective event where an OTDR cannot detect another event, so closely spaced splices or connectors may be hidden and need testing from both ends.

The force applied to a cable during installation, which must stay within the maker's limit and be applied to the strength member, not the fibers, to avoid strain and loss.

Safety gear such as safety glasses, gloves and cut-resistant sleeves worn during splicing to guard against flying glass shards, laser light and sharp tools.

The practice of never looking into a fiber or connector, using a visual fault locator only as intended, and keeping sources capped, because invisible infrared light can damage eyes unseen.

Collecting stripped glass scraps in a sealed sharps container, never on the floor or in clothing, so they cannot injure workers or contaminate food and waste streams.

The final record of what was actually installed, including cable routes, fiber assignments, splice tables and test results, handed to the client for future maintenance and fault finding.

A table listing each fiber, its cable and tube position, the closure it passes through and the fiber it is joined to, used to plan work and verify joints.