The Research Of Multifunctional EDFA

With the extensive development of the internet, the demand for the amount of data is increased quickly. The traditional communication technology has been difficult to meet today's growing demand for high-speed data, optical communications technology just meet this demand. Because of the incomparable advantages of optical communication technology in high-capacity, long-distance transmission system has been widely used in optical fiber communication systems and networks. The erbium-doped fiber amplifiers in optical fiber communication system is very impressive device, because it has low noise, high gain and high pump efficiency, wide frequency band and other excellent features, such as low insertion loss, transparent to the transmission bit rate and format, etc. It is the ideal component in modern optical fiber communication system.But when the erbium-doped fiber amplifier is used for high-speed and ultra high-speed DWDM systems, there will be a lot of problems, including:①amplifier gain flatness,②automatic gain control,③power automatic control,④dispersion compensation and the spontaneous emission noise filter,⑤cascaded amplifier PMD, PDL, PDG and so on. These problems can seriously affect the performance of DWDM transmission systems. It is very necessary for us to solve these problems.The thesis mainly researched the EDFA gain control, gain-flattened and dispersion compensation, along with a brief introduction of the power control and temperature control principles. Finally a multifunctional fiber amplifier transmission system is realized in the laboratory.In this paper, firstly there is a brief introduction on basic knowledge which is used in the thesis, including the EDFA gain characteristics, noise characteristics and multi-channel amplification characteristics, as well as basic characteristics of fiber grating. Secondly, there is a basic introduction on the automatic power control (APC) and temperature control features. The current technologies on circuit-based power control and temperature control have been very mature.There is a detailed study on the gain flatness and automatic gain control characteristics in the main body of the article. Gain flatness is mainly realized through the long-period fiber gratings and FBG. Then several solutions on automatic gain control is introduced. We select all-optical automatic gain control solution, which is realized through the FBG and the variable attenuator to form a feedback loopFinally, the multi-fiber amplifier is achieved. High-speed DWDM systems successfully transmit four-way signals for400kilometers.