In SMF, the diameter of the core is too small means 10 microns. Due to its small core diameter, only a single mode of light can be propagated. Also, the coupling light in this cable becomes difficult due to small core of the cable. It uses an infrared laser as light source. Another purpose of using laser as light sources is to achieve high bandwidth. The light ray that carries the data is transmitted in a straight line and therefore enhances the speed of data transmission.
The primary advantage of SMF over MMF is that it can support higher segment lengths. For instance, SMF is able to support a segment length of 5000 meters and higher over all the Ethernets having a data transmission rate of up to 1 Gbps. With the advantages, SMF has some disadvantages too. The major disadvantage of SMF is that the installation cost is higher than MMF.