光纖中繼器主要由光近端機、光纖、光遠端機(覆蓋單元)幾個部分組成。光近端機和光遠端機都包括射頻單元(RF單元)和光單元。無線信號從基站中耦合出來後，進入光近端機，通過電光轉換，電信號轉變為光信號，從光近端機輸入至光纖，經過光纖傳輸到光遠端機，光遠端機把光信號轉為電信號，進入RF單元進行放大，信號經過放大後送入發射天線，覆蓋目的地區域。上行鏈路的工作原理一樣，手機發射的信號通過接收天線至光遠端機，再到近端機，回到基站。

數位光纖直放站採用了軟體無線電技術、數位濾波技術、數位傳輸技術，克服類比光纖傳輸受距離限制的缺點，滿足遠距離傳輸時所需要的大動態、低雜訊的要求。數位光纖直放站在硬體平臺不變的情況下，通過升級設備軟體，即可實現設備功能的拓展，使用靈活、方便。數位光纖直放站無論在頻率選擇特性、抗干擾能力，以及功能拓展方面均遠遠優於類比光纖直放站。

The optical fiber repeater is mainly composed of optical near-end machine, optical fiber, and optical remote machine (covering unit). Both the optical near-end machine and the optical remote machine include a radio frequency unit (RF unit) and an optical unit. After the wireless signal is coupled from the base station, it enters the optical near-end machine, through electrical-to-optical conversion, the electrical signal is converted into an optical signal, from the optical near-end machine to the optical fiber, and transmitted to the optical remote machine through the optical fiber. The signal is converted into an electrical signal and enters the RF unit for amplification. After the signal is amplified, it is sent to the transmitting antenna to cover the destination area. The working principle of the uplink is the same. The signal transmitted by the mobile phone passes through the receiving antenna to the optical remote machine, then to the near-end machine, and returns to the base station.

  The digital optical fiber repeater uses software radio technology, digital filtering technology, and digital transmission technology to overcome the shortcomings of analog optical fiber transmission that is limited by distance, and meet the requirements of large dynamics and low noise required for long-distance transmission. When the hardware platform of the digital optical fiber repeater is unchanged, the function of the device can be expanded by upgrading the device software, which is flexible and convenient to use. Digital fiber optic repeaters are far superior to analog fiber optic repeaters in terms of frequency selection characteristics, anti-interference ability, and function expansion.