A data transmitting device ( e.g network switch, computer etc) sends a signal via a lightwave down the cable, bouncing the signal down the fibres to another device which receives and interprets the signal. The fibres are hair thin, at about 0.125mm each. These cables are used in transmitting data over long distances and replace older copper communications cabling. Copper cabling in premise has a maximum use of 90m whereas depending on the fibre type, these cables can be run for kilometers.
The transmission speed of fibre optics is unrivalled versus copper cabling. A CAT6 Cable has a maximum transmission speed of about 10Gigabits/second over about 40m. Fibre optics over the same length can be (dependent on type and configuration) 100 Gigabits/second. That a 10x increase in transmission speeds!
Singlemode? Multimode? OS1? OM4? LC? ST? Pigtail? What does all this mean? In short, these are terminology used to differentiate fibre optic types, connectors and accessories. Below is a short summary of each type and its characteristics
Singlemode- Thinner core, can transmit higher data speeds
Multimode- Thicker core, can transmit lower data speeds
OS1/2- details it is a "optical singlemode" generation 1 or 2
OM1/2/3/4- details it is a "optical multimode" generation 1-4
LC/ST/SC/FC- fibre optic connector types- the end that you see and can patch cables in/out of to complete the final join to the device
Pigtail- the small lead that is fusion spliced to the end of a cable, with a connector built in, to enable connection to the final device.