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Are you stupid enough to tell the difference between single-mode fiber and multi-mode fiber?

According to the transmission mode of light in the optical fiber, it can be divided into: single-mode optical fiber and multi-mode optical fiber. Although there is only one word difference between single-mode and multi-mode, there is some difference in performance. Are you still foolish enough to distinguish between single-mode fiber and multi-mode fiber?

single mode fiber

Single-mode fiber: It can only transmit signal waves of one mode. Because the single-mode fiber only propagates along a straight line and has no reflection, there is no modal dispersion, which makes the transmission frequency band of the single-mode fiber very wide, so it is suitable for backbone, large-capacity, and long-distance systems. Light-emitting diodes or lasers are used as light sources, and two wave bands of 1310nm and 1550nm are used. The central glass core of the single-mode optical fiber is very thin (the core diameter is generally 9 or 10 μm), and it is much thinner than the multi-mode optical fiber in terms of appearance.

Multimode fiber

Multimode optical fiber: It can carry the transmission of multiple optical signals, that is, multiple optical paths can transmit multiple modes of light in one optical fiber at the same time. Because there are multiple modes of transmission, there is a large intermodal dispersion. The transmission performance is poor, the frequency band is narrow, and the capacity is small. Therefore, the transmission distance of multimode fiber is relatively short.Generally only a few kilometers, and is often used in small-capacity, short-distance systems. The multimode fiber uses laser as the light source and uses two wave bands of 850nm and 1300nm. The central glass core of the multimode fiber is relatively thick (50 or 62.5μm).

In terms of price, under the same specifications, single-mode will be more expensive than multi-mode. From the perspective of practical application, multi-mode is basically used for data access optical cables. Compared with single-mode, the biggest disadvantage of multi-mode is Intermodal dispersion (due to different velocities of the same light in different modes). In China, 62.5/125 multimode optical fiber is mainly used. As for the difference between the two, it seems that the purpose of cable is different. 50 is mostly used for indoor optical cables.

Judging from the appearance color, the single-mode fiber is all yellow, the gigabit multi-mode is orange-red, and the 10-gigabit multi-mode is light blue.

The difference between multimode fiber and single-mode fiber is mainly in the way of optical transmission, and of course the bandwidth capacity is also different. The diameter of the multimode fiber is large, and the light beams of different wavelengths and phases are continuously reflected along the fiber wall and transmitted forward, 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 thin, and the light travels in a straight line without reflection, so the dispersion is reduced, the bandwidth is increased, and the transmission distance is also lengthened. However, the price of the matching optical end equipment is relatively high, and the bandwidth of the single-mode optical fiber exceeds 10Gbps.

After reading the above content, do you still not know the difference between single-mode fiber and multi-mode fiber? If you have optical fiber needs, please contact sales@hj-net.com for product order.