The working principle of optical fiber repeater

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The working principle of optical fiber repeater

A fiber optic repeater is a repeater that uses optical fiber for signal transmission. The use of optical fiber has the characteristics of low transmission loss, convenient wiring, and suitable for long-distance transmission. It can solve the problem that villages, towns, tourist areas, highways, etc. cannot receive base station signals. Fiber optic repeater can also solve the problem of signal coverage in large and very large buildings, such as those used in large high-rise regional buildings (groups), and communities with higher requirements.


With the rapid development of China's mobile communication industry, the number of mobile communication users is increasing, the cellular planning is getting smaller and smaller, and the location of optical fiber repeater is getting lower and lower. On the other hand, with the construction of high-rise cities, high-rise buildings are constantly emerging. Due to the shadow effect of wireless transmission, blind or weak areas of mobile communication signals are often formed behind or in the middle of these high-rise buildings. In addition, in the construction process of the cellular mobile base station, due to the interference problem of adjacent cells, the main lobe of the antenna radiation field pattern has a large downtilt angle, and therefore, the middle and upper parts of the high-rise building cannot effectively receive signals. This is the reason why people study fiber optic repeater.

In addition, in some closed large buildings, such as tunnels, subways, underground shopping centers, parking lots, hotels, and office buildings, mobile communication signals cannot generally be received due to the shielding effect of buildings and the like against electromagnetic waves.

Fiber repeater is mainly composed of fiber near-end machine, fiber and fiber far-end machine (covering unit). Both the optical near end machine and the optical far end machine comprise a radio frequency unit and an optical unit. After the wireless signal is coupled from the base station, it enters the optical terminal through electro-optical conversion, converts the electrical signal into an optical signal, from the optical terminal to the optical fiber, and then transmits to the optical remote machine through the optical fiber. The signal is converted into an electrical signal and enters the radio frequency unit for amplification. After the signal is amplified, it is sent to the transmitting antenna to cover the target area. The uplink works on the same principle. The signal sent by the mobile phone reaches the optical remote machine through the receiving antenna, then reaches the near-end machine, and then returns to the optical fiber repeater. This is the working principle of fiber optic repeater.