Semi tight buffered cable
Type of cable construction whereby each glass fiber is buffered by a protective thermoplastic coating to a diameter of 900 micrometers which can be easily striped at portions longer than 15cm.

Short wavelength
Light whose wavelength is shorter than 1,000 nanometers. (shorter than one micron or 1 µm.)

Short wavelength coupler
Single mode fibre optic coupler witch is designed to work at wavelengths shorter than 1,000 nanometers.

Short wavelength single mode fibre
Single mode fibre with cutoff wavelength that allow high bandwidth to be transmitted at short wavelength.

Singlemode fibre
A fibre with a small core, usually between 2 and 9 microns that can only support one wavelength.

Simplex cable
A single fiber with at least one layer of protective jacketing for environmental protection and ease of handling. May also include strength members or external armoring. 

SMF
Singlemode fibre. 

SNR
Signal To Noise Ratio: The relationship between the usable intended signal and extraneously present noise present, usually measured at the source. It is expressed in dB. If the SNR limit is exceeded the signal transmitted will be unusable.

Splitting ratio (SR)
Percentage division ratio of the optical input signal to the output signals for an optical coupler or splitter with more than 2 outlets.

Step index fibre
An optical fibre that has a uniform core index and a lower uniform cladding index, creating a step change in refractive index profile.

Strength member
A rigid or flexible element, such as a glass-reinforced plastic rod or aramid yarn, used in cabling fibre to achieve increased tensile strength.