- Fibre Optic Jargon
Jargon
What is fibre optics?
Picture sending signals zipping along from one location to another in the form of light guided through thin fibres of glass or plastic. These signals can be analogue or digital - voice, data or video information and fibre can transport more information longer distances in less time than any copper wire.
It's powerful and fast, fast, fast!
First get to know the language - the "jargon" - here's a list of terms you should get to know:
Metric System: Fibre Optics, as a universal technology, utilises the metric system as the standard form of measurement. Several of the more common terms:
Meter: 39.37 inches.
Kilometre: 1000 meters / 3,281 feet / 0.62 miles.
Micron: 1/1,000,000 th of a meter. 25 microns equal 0.001 inch.
This is the common term of measurement for fibres.
Nanometre: One billionth of one meter. This term is commonly
used in the fibre optics industry to express wavelength or frequency
of transmitted light.
Let's Start With fibre
Optical fibre: Thin strands of highly transparent glass or sometimes plastic that guide light.
Core: The centre of the fibre where the light is transmitted.
Cladding: The outside optical layer of the fibre that traps the light in the core and guides it along - even through curves.
Buffer coating or primary coating: A hard plastic coating on the outside of the fibre that protects the glass from moisture or physical damage.
Mode: A single electromagnetic field pattern (think of a ray of light) that travels in fibre.
Multimode fibre: has a bigger core (almost always 62.5 microns - a micron is one one millionth of a meter - but sometimes 50 microns) and is used with LED sources at wavelengths of 850 and 1300 nm for short distance, lower speed networks like LANs.
Singlemode fibre: has a much smaller core, only about 9 microns, and is used for telephony and CATV with laser sources at 1300 and 1550 nm. It can go very long distances at very high speeds.
Both multimode and singlemode fibre have an outside diameter of 125 microns - about 5 thousandths of an inch - just slightly larger than a human hair.
Plastic optical fibre (POF): is a large core (about 1mm) multimode fibre that can be used for short, low speed networks. POF is used in consumer HiFi and starting to be used as part of a new standard for car communication systems called MOST (go to http://www.mostcooperation.com/)
For more on optical fibre, go here.
Terms that describe fibre optic cable:
Cable: fibre needs protection to survive all the places it gets installed and it's the cable that provides it. Cables may have from one to hundreds of fibres inside.
Jacket: The tough outer covering on the cable.
Cables installed inside buildings must meet fire codes by using
special jacketing materials.
Strength members: Aramid fibres (Kevlar is the duPont trade name) used to pull the cable. The term is also used for the fibreglass rod in some cables used to stiffen it to prevent kinking.
Armour: Discourages rodents from chewing through it.
(Go here for more on cables)
Termination:
Connector: A non-permanent device for connecting
two fibres or fibres to equipment 
where
they are expected to be disconnected occasionally for testing
or rerouting. It also provides protection to both fibres. (Parts
for an ST connector are shown.)
Ferrule: A tube which holds a fibre for alignment, usually part of a connector
Splice: a permanent joint between two fibres
Mechanical Splice: A splice where the fibres are aligned created by mechanical means
Fusion Splice: A splice created by welding or fusing two fibres together
Fusion Splicer: An instrument that splices fibres by fusing or welding them, typically by electrical arc.
Hardware: Terminations and Splices require hardware for protection and management: patch panels, splice closures, etc.
(Here's more on terminations)
Fibre Performance Specifications
Terms you use when you want to take your measurements:
Attenuation: The reduction in optical power as it passes along a fibre, usually expressed in decibels (dB). See optical loss
Bandwidth: The range of signal frequencies or bit rate within which a fibre optic component, link or network will operate.
Decibels (dB): A unit of measurement of optical power which indicates relative power. A -10 dB means a reduction in power by 10 times, -20 dB means another 10 times or 10 times overall, -30 means another 10 times or 1000 times overall and so on.
dB: Optical power referenced an arbitrary zero level
dBm: Optical power referenced to 1 milliwatt
Micron (m): A unit of measure used to measure wavelength of light.
Nanometre (nm): A unit of measure used to measure the wavelength of light (meaning one one-billionth of a meter)
Optical Loss: The amount of optical power lost as light is transmitted through fibre, splices, couplers, etc, expressed in dB.
Optical Power: is measured in "dBm", or decibels referenced to one milliwatt of power. while loss is a relative reading, optical power is an absolute measurement, referenced to standards. You measure absolute power to test transmitters or receivers and relative power to test loss.
Scattering: The change of direction of light after striking small particles that causes loss in optical fibres and is used to make measurements by an OTDR
Wavelength: A term for the colour of light, usually expressed in nanometres (nm) or microns (m). fibre is mostly used in the infrared region where the light is invisible to the human eye.
Go here for more information on testing.
Terms that describe the tools you will need for installation and termination:
Jacket Slitter or Stripper: A cutter for removing the heavy outside jacket of cables
fibre Stripper: A precise stripper used to remove the buffer coating of the fibre itself for termination. There at three types in common use, called by their trade names: "Miller Stripper", "No-Nik" and "Micro Strip."
Cleaver: A tool that precisely "breaks"
the fibre to produce a flat end for polishing or splicing.
Scribe: A hard, sharp tool that scratches the fibre to allow cleaving.
Polishing Puck: for connectors that require polishing, the puck holds the connector in proper alignment to the polishing film.
Polishing Film: Fine grit film used to polish the end of the connector ferrule.
Crimper: A tool that crimps the connector to the aramid fibres in the cable to add mechanical strength.
Here is more information on termination.
Terms that describe test equipment you will need:
Optical Power Meter: An instrument that measures optical power from the end of a fibre
Test Source: an instrument that uses a laser or LED to send an optical signal into fibre for testing loss of the fibre
Optical Loss Test Set (OLTS): A measurement instrument for optical loss that includes both a meter and source
Reference Test Cables: short, single fibre cables with connectors
on both ends, used to test unknown cables.
Mating Adapter: also called splice bushing or couplers,
allow two cables with connectors to mate.
Fibre Tracer: An instrument that allows visual checking of continuity and tracing for correct connections
Visual Fault Locator: A device that allows visual tracing and testing of continuity.
Microscope: used to inspect the end surface of a connector for flaws or dirt.
OTDR: An instrument that uses back scattered light to find faults in optical fibre and infer loss from only one end of the cable.
For more on testing, go here.
For a complete glossary, go here.
