SC - A connector type. It is primarily used with single-mode fiber optic cables. It offers low cost, simplicity and durability. Furthermore, it provides for accurate alignment by a ceramic ferrule. It is a push on -pull off connector with a locking tab. It is similar to the connector used for FDDI but is not compatible.
Scattering - A property of glass which causes light to deflect from the fiber optic cable and contributes to losses.
SDM - Space Domain Multiplexing
Semiconductor Laser - Same as a laser diode.
Sensitivity - For a fiber optic cable receiver it is the minimum optical power required to achieve a specified level of performance, such as BER. Alternatively, it is the minimum amount of energy required by a receiver for successful operation.
Shot noise - Noise caused by random current fluctuations arising from the discrete nature of electrons.
Signal to noise ratio - The ratio of signal power to noise power.
Silica - Glass material, nearly pure SiO2.
SI-POF - Step index plastic fiber optic cable.
Simplex cable - A term sometimes used for a single-fiber cable.
Single-mode - A small core, fiber optic cable that supports only 1 mode of light propagation above the cutoff wavelength. Typically, the diameter of the core is 9-10 mm. Dispersion and power loss through the cable walls are low with this type of cable. It is proper for long distance transmission.
SMA - A connector type. This was the predecessor of the ST connector. It features a threaded cap and housing. The use of the SMA connector has decreased markedly in recent years being replaced by the ST and SC connectors.
SNR, S/N - Signal to noise ratio. Usually expressed in dB.
Soliton - An optical pulse that does not suffer dispersion as it propagates over a distance.
SONET - Synchronous Optical Network. An international standard for fiber optic cable based telephony.
Source - There is 2 possibilities. First, it is a generator of information or data. Secondly, within the context of fiber optics it is a light emitter, either an LED or laser diode, for a fiber optic cable based link.
Spectral attenuation - Measure for the attenuation in dependence on wavelength.
Spectral bandwidth (Between half power points) - It is the wavelength interval in which a radiated spectral quantity is not less than half its maximum value. It is a measure of the extent of the spectrum. For a light source typical spectral widths are 20 to 60 nm for a LED and 2 to 5 nm for a laser diode.
Spectral width - The measure of the wavelength extent of a spectrum. It is usually based upon the 50% intensity points. When referring to the spectral width of sources, typical spectral widths are 20 to 60 nm for a LED and 2 to 5 nm for a laser diode.
Splice - An interconnection method for joining the ends of 2 fiber optic cables in a permanent or semi-permanent fashion. Thermal fusing may carry out splicing or it may be mechanical.
Splicing - The permanent joining of fiber optic cable ends to identical or similar fiber optic cables without using a connector. See also Fusion splicing and Mechanical splicing.
Splice box - Housing for 1 or more splice organizers. The changeable front panel can be equipped with different connector plugs.
Splice closure - A container used to organize and protect splice trays.
Splice organizer - An organizer panel that holds up to 12 splices with splice protectors and sufficient loops.
ST - A keyed bayonet connector type similar to a BNC connector. It is used for both multi-mode and single-mode fiber optic cables. Its use is wide spread. It has the ability both to be inserted into and removed from a fiber optic cable both quickly and easily. Method of location is also easy. There are 2 versions ST and ST-II. These are keyed and spring loaded. They are a push in and twist type.
Star coupler - A coupler for a fiber optic cable in which power at any input port is distributed to all output ports.
Star network - A network in which all terminals is connected through a single point, such as a star coupler.
Steady state - Equilibrium mode distribution.
Step index fiber - A fiber optic cable, either multi-mode or single-mode, in which the core refractive index is uniform throughout so that a sharp step in refractive index occurs at the core-to-cladding interface.
Step index profile - A refractive index profile in which the refractive index changes abruptly from the value n1 to n2 at the core cladding interface.
Strength member - That part of a fiber optic cable composed of Kevlar Aramid yarn, steel strands or fiberglass filaments that increases the tensile strength of the cable.
Stripping - Removing the coating from a fiber optic cable.
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