The transmission distance of the optical transceiver is divided into short distance, medium distance and long distance. Usually short-distance transmission refers to the transmission distance below 2km, medium distance is 10-20km, and ≥30km is long-distance transmission. In the fiber transmission, common wavelength is 850nm, 1310nm, and 1550nm, which the attenuation of the optical fiber is relatively small, and these three wavelengths have almost zero absorption, which is most suitable for optical fiber transmission. From the analysis of the commonly used wavelengths of optical transceivers, it is not difficult to conclude that for short-distance transmission, the wavelength of 850nm is generally used within 500m; the wavelength of 1310nm is commonly used from 500m to 20km; the wavelength of 1310nm and 1550nm can be selected for 20-40km; Here are some commonly used wavelengths and their characteristics.
It is a multi-mode communication method with relatively large attenuation, and the price of the light source transmitter and signal converter matched with the 850nm optical transceiver is far lower than the price of 1310nm and 1550nm devices, which is a very economical communication method. Therefore, most multimode optical fibers use optical transceivers with a working wavelength of 850nm for connection and transmission. Under the wavelength of 850nm, the 100M optical transceiver can transmit up to 2km, Gigabit can transmit up to 550m, 10G can transmit up to 300m, 40G can transmit up to 400m, and 100G and 400G can transmit up to 100m.
The attenuation of optical fiber to 1310nm is about 0.35dB/km. With multi-mode, the longest transmission distance is 2km, and with single-mode, the longest transmission distance is 40km. At 1310nm wavelength, 100M, 1000M, 10G, 40G, 100G optical transceivers can transmit up to 40km, and 400G can transmit up to 500m.
The attenuation of the optical fiber to 1550nm is relatively small, about 0.19dB/km. Therefore, with the same Tx power, the 1550nm wavelength can be sent farther than the 1310nm wavelength. Under 1550 wavelength, the maximum transmission distance of 100M and 1000M optical transceivers can reach 160km, and the maximum transmission distance of 10G optical transceivers can reach 80km. 40G, 100G optical transceivers usually choose to use CWDM or DWDM if the transmission distance exceeds 40km.