First of all, we must understand that both single-mode fiber and multi-mode fiber are used to transmit high-quality network signals over long distances. The reason for distinguishing single-mode and multi-mode is based on the way light propagates inside it; light in a single-mode fiber propagates along a straight line without reflection, so its propagation distance is very long. The multimode fiber can carry the transmission of multiple optical signals.

1.The single-mode fiber has a small diameter (about 10mm), only allows one mode to transmit, and has a small dispersion. The operating wavelengths are 1310nm and 1550nm, and it is difficult to couple with optical devices.

2. The multimode fiber has a large diameter (62.5mm and 50mm), allows hundreds of modes to transmit, and has large dispersion. The operating wavelengths are 850nm and 1310nm, and the coupling with optical devices is relatively easy.

For optical modules, there is no single-mode or multi-mode distinction. The so-called single-mode multi-mode module refers to the optimal transmission characteristics obtained by the combination of optical components and optical fibers used in the optical module.

​Second, from the perspective of external light, the most conventional method for distinguishing is: the yellow optical fiber is generally single-mode fiber, and the orange-red or gray optical fiber is generally multi-mode fiber. The difference between the two in the cable core is that the multimode cable core size is 50.0μm and 62.5μm; while the single mode is 9.0μm.




Third, the two optical fibers we saw above all have LC interfaces, so in addition, the optical fibers have a very rich selection of interfaces.