Study Of Wideband Fiber Amplifiers And Tunable Erbium-Doped Fiber Lasers

This work comes from the Key Program of Tianjin Science and Technology Development Plan (2003), i.e. 'Development of wideband tunable fiber lasers for communication application'. The contents of the fundamental work related to this program are as follows:1. Theoretic analysis and experimental research of L-band erbium-doped fiber amplifier (EDFA)Analysis of gain characteristic of L-band EDFA; Simulation of gain characteristic in small signal condition using numerical computation, which theoretically verified the intrinsic flat gain characteristic of L-band EDFA; Experimental research of L-band EDFA, achieving expected results of improved pump efficiency2. Experimental research of EDFA gain flatnessExperimenting on gain flatness issue of C-band EDFA employing a fiber loop mirror (FLM) and a long period fiber grating (LPFG) respectively and both achieving average gain about 20dB and variation less than ±0.9dB in a range of 30nm; numerical and experimental research of L-band EDFA gain characteristic with different EDF lengths; comb-like filtering of L-band flattened ASE spectrum using a F-P filter and acquiring a multi-wavelength ASE source of 30nm wide; Experimenting with series structure C+L band EDFA and achieving a flattened gain as wide as 70nm.3. Experimental research of tunable fiber laserExperimenting with C-band tunable erbium-doped fibers (EDFLs) using filters based on fiber loop mirror (FLM), wedge thin-film F-P and angle tuning thin-film F-P, achieving line-width of 0.8nm, 0.1nm and 0.1nm respectively. Experimenting with L-band tunable EDFL using a conventional FLM, achieving tunable range about 40nm and line-width of 0.8nm; compressing line-width using compound filters based on Lyot and Solc type FLMs, achieving tunable laser output with line-width<0.1nm in a range of 40nm. Experimenting with C+L band EDFL applying conventional FLMs, achieving tunable range of 60nm and line-width of 0.8nm.4. Research of fiber Raman amplifier (FRA) designStudy and discussion of FRA's amplification characteristics; theoretically analysis of effects of employing distributed FRAs on improving system performance; Analysis of gain flatness of multi-wavelength pumped FRA and optimization of FRA+EDFA wide band amplifier design.