光放大器补偿长距离链路的传输损耗和接入网上的分支损耗 ,同时避免了光 -电信号间昂贵的双向转换。迄今 ,可利用的器件主要以掺稀土的有源光纤光放大器为代表 ,本文介绍通信用光放大器的发展水平。近几年掺铒光纤放大器以其优质商品投入市场 ,广泛应用于在第三传输窗口中传输的长距离网络上 ;而在第二传输窗口中 ,半导体光纤放大器仍有竞争力。 The optical amplifier compensates for the transmission loss of long-haul links and the branch loss on the access network while avoiding the expensive bidirectional conversion between optical and electrical signals. So far, the available devices are mainly represented by rare earth-doped active optical fiber optical amplifiers. This article introduces the development of optical amplifiers for communications. In recent years, erbium-doped fiber amplifiers have been put into the market with their high-quality goods and are widely used in long-haul networks transmitted in the third transmission window. In the second transmission window, semiconductor optical fiber amplifiers are still competitive.