Fibre cables have the ability to transfer data over long distances, and at high speed. This article discusses the differences between the multi-mode optical fibre and single-mode optical fibre, and the distances that can be expected from these two types of fibre optic cables for data transfer at rates from 100Mb to 40G.
Fibre optic cables are extremely thin wires of high-purity silica glass, with the ability to transmit light from one end of the cable to the other end with minimum loss to the data. These optic cables are manufactured in a variety of specifications, based on the type of material used for construction, the number of fibres present within.
Fibre optic cables are generally differentiated into 2 types – Multi-mode fibre optic cables and Single-mode fibre optic cable.
They can carry multiple light rays (modes) at the very same time due to the different materials present in their core. There are multiple modes of light pulse transmission due to the larger core diameter, which allows for simplified connections. The light rays with the shortest distance to travel (through the middle of the core) will be the slowest. The multimode cables generally have 50-100 microns diameter. Over medium distances, these cables offer higher bandwidth and higher speeds. These optical fibre cables are considered better suited to ‘domestic’ needs and are used for local-area networks, like the FTTH, and also reach up to 100Gbps speeds in Ethernet.
A single-mode optical fibre cable is about 8.5-10microns diameter in size and is designed to carry light pulses directly over long distances up to 100km. It is a single strand of glass fibre as the name suggest. With a single mode of transmission, it can propagate 1310 or 1550 nm. Single-mode optic fibre is generally used for long-distance LAN’s, Cable TV and telephone applications.
Compared to multimode cables, the single-mode has increased bandwidth and can transmit up to 50 times higher distance, due to its smaller core.