Single-mode fiber patch cable is a type of patch cable used for the connection of two network device ends. As for the meaning of single-mode, it is a form of data transmission which uses only one single path to transmit light signals. This greatly reduces the signal loss during the transmission process, thus single-mode fiber patch cable is normally used for long distance transmission. It only restricts the mode of waves not the frequencies, therefore multiple waves can join in the fiber with different frequencies. And single-mode fiber patch cable has its own yellow color to make a distinction from other mode fiber patch cables.