According to the transmission mode of light in the fiber, it can be divided into: single-mode fiber and multi-mode fiber. There is only one word difference between single-mode and multi-mode, so what is single-mode fiber and multi-mode fiber, what is the difference between the two, just the difference in the number of simple modes? The following will take you to understand what is single-mode fiber and multi-mode fiber.
Carrier-grade single-mode single-core fiber optic cable
Only one mode of signal wave can be transmitted. Because the single-mode fiber only propagates along a straight line without reflection, there is no modal dispersion, which makes the transmission band of the single-mode fiber very wide, so it is suitable for trunk, large-capacity, and long-distance systems. The light-emitting diode or laser is used as the light source, and two bands of 1310nm and 1550nm are used. The central glass core of the single-mode fiber is very thin (the core diameter is generally 9 or 10 μm), which is much thinner than the multi-mode fiber in terms of appearance.
Multimode fiber
It can carry the transmission of multiple optical signals, that is, multiple optical paths can transmit multiple modes of light in one fiber at the same time. Since there are multiple modes of transmission, there is a large intermodal dispersion, and its transmission performance is poor. , The frequency band is narrow and the capacity is small. Therefore, the distance of multimode fiber transmission is relatively short, generally only a few kilometers, and is often used in small-capacity, short-distance systems. The multimode fiber uses a laser as the light source and uses two bands of 850nm and 1300nm. The central glass core of the multimode fiber is thicker (50 or 62.5 μm).
What is single-mode fiber and multi-mode fiber? In terms of price, under the same specification, single-mode will be more expensive than single-mode. The biggest disadvantage relative to single mode is intermodal dispersion (due to the different rates of the same light in different modes). In China, 62.5/125 multimode fiber is mainly used. As for the difference between the two, it seems that the use of the cable is different, and the 50 fiber is mostly used for indoor optical cables.
Judging from the appearance and color, all single-mode fibers are yellow. The gigabit multi-mode is orange-red, and the 10-gigabit multi-mode is light blue.
Summarize:
Optical fibers are divided into multimode fibers and single-mode fibers. The difference between multimode fibers and single-mode fibers is mainly in the different modes of light transmission, and of course, the bandwidth capacity is also different. The diameter of the multimode fiber is large, and the beams of different wavelengths and phases are continuously reflected and transmitted along the fiber wall, causing dispersion, which limits the transmission distance and bandwidth between the two repeaters. The bandwidth of the multimode fiber is about 2.5Gbps. The diameter of the single-mode fiber is relatively small, and the light travels in a straight line in it and is rarely reflected, so the dispersion is reduced, the bandwidth is increased, and the transmission distance is also extended. However, the price of the supporting optical terminal equipment is relatively high, and the bandwidth of single-mode fiber exceeds 10Gbps.
In security applications, the most common determinant of choosing between multimode or singlemode is distance. If it is only a few hundred meters, multimode is preferred because LED transmitter/receivers are much cheaper than lasers required for single mode. If the distance is greater than 10km, single-mode fiber is the best. Another issue to consider is bandwidth; if future applications may include the transmission of large bandwidth data signals, then single mode will be the best choice.
Carrier-grade single-mode single-core fiber optic cable application scenarios
Through the introduction of ZR Fiber, I believe that everyone has an understanding of what single-mode fiber and multi-mode fiber are. If you want to know more about ZR optical fiber series products, welcome customers to come to consult.
