How to distinguish between single mode fiber and multimode fiber

How to distinguish between single mode fiber and multimode fiber

The difference between single-mode and multi-mode fiber transceiver

According to the transmission mode of light in optical fiber, it can be divided into: single mode fiber and multimode fiber


The core diameter of    multimode fiber is 50~62.5μm, the outer diameter of cladding is 125μm, the core diameter of single mode fiber is 8.3μm, and the outer diameter of cladding is 125μm. The working wavelength of the optical fiber has short wavelength 0.85μm, long wavelength 1.31μm and 1.55μm. Fiber loss generally decreases with increasing wavelength. The loss of 0.85μm is 2.5dB/km, the loss of 1.31μm is 0.35dB/km, and the loss of 1.55μm is 0.20dB/km. This is the lowest loss of the fiber and the wavelength is 1.65 The loss above μm tends to increase. Due to the absorption effect of OHˉ, there are loss peaks in the range of 0.90~1.30μm and 1.34~1.52μm, which are not fully utilized. Since the 1980s, single-mode optical fibers have tended to be used, and the long wavelength of 1.31 μm was used first.

Dielectric Loose Tube Fiber Optic Cable GYFTY

Multimode fiber

Multi-mode fiber (Multi Mode Fiber): The center glass core is thicker (50 or 62.5μm) and can transmit multiple modes of light. However, the dispersion between the modes is large, which limits the frequency of transmitting digital signals, and will become more serious as the distance increases. For example: 600MB/KM optical fiber has only 300MB of bandwidth at 2KM. Therefore, the transmission distance of multimode fiber is relatively short, generally only a few kilometers.

Post time: Jul-14-2020