Study Of All-optical Gain-clamped Erbium-doped Fiber Amplifier

Erbium-doped fiber amplifier(EDFA) is a key device in the area of optical fiber communication. But it has a nonflat gain-versus-wavelength profile, which greatly varies because of saturation when the input power levels are large. In the design of optically amplified links for WDM applications, in which the number and power level of the input channels may vary randomly in time as in a network scenario, it is thus essential to stablize the amplifier gain profile.This thesis is devoted to research on all-optical gain-clamped fiber amplifier to address the above problems. It is firstly studied the gain-clamped mechanism of erbim-doped fiber amplifier. We find a solution to obtain high gain with large output power over gain-clamped erbium-doped fiber amplifier. Then we examine and analyze the relevant factors which affect the characteristics of amplifier. Based on our theoretical predictions, we find optimal splicing parameters on FSM-30S fiber splicer for low loss joints between erbium doped fiber and other single mode fibers. We also experimentally demonstrate a novel three-stage erbium-doped fiber amplifier with high gain, low noise figure, and high output power. Finally, a prototype of a gain-clamped fiber amplifier is obtained with high gain(26 dB), low noise figure (5.3 dB), high output power(17 dBm), and large bandwidth(31 nm). The erbium doped fiber amplifier has been tested in the Direct Amplifier Station of Institute of Fujian Telecommunications for the first time in China. The experiment was very successful.Candidate:Qiang Zexuan(Optics)Directed by:professor Chen Zhihao...