Erbium Doped Fiber Amplifier for multi-channel transmission : Special issue on optical transmission components

This paper discusses our Erbium Doped Fiber Amplifiers (EDFAs) modules for multi-channel transmission systems and an optical gain equalizer which passively equalizes gain variance of EDF. First of all, we describe our newly developed EDFA module using the passive gain equalizer which achieved a gain flatness of 0.37 dB p-p in 26nm bandwidth. Next, we describe the design of optical gain equalizer. This device consists of four etalon filters, and has loss characteristics which compensate the gain profile of erbium doped fiber. Finally, we describe a nextgeneration EDFA module which has a unique dynamic equalizing function which we have proposed for the first time in the world. In this module, we have achieved ultra low gain flatness of 0.09 dB p-p in 26 nm.