Pivotal Techniques Of Broadband Erbium-doped Fiber Amplifier(EDFA)

As the key device of WDM system, the behavior of erbium-dopedfiber amplifier(EDFA) will directly influence the transmissionbandwidth and distance of the system. In this dissertation some pivotaltechniques of EDFA were investigate and experimentally studied withthe productions as follows:1. Theoretical analysis and optimization of C band and L band EDFAand experimentsBased on the rate-equations and propagation equations, the stable stateoutput property of EDFA was fully studied using self-made computerprograms. With these programs EDFA of different functions weredesigned and optimized. High gain low noise figure C band and L bandpreamplifier have been realized in our experiments with the G>31.5dB,NF <4.76dB and G>38.84dB,NF<5.29dB respectively.2.Experiment on the C+L band broadband EDFA1) With the C and L band EDFA combined in parallel connection scheme,broadband gain above 30dB were achieved with the 3dB gain bandwidthof 57nm which including 25nm(1530nm～1555nm)in C band and32nm(1570nm～1602nm) in L band.2)We give the first report on the experimental studies of bismuth-basederbium-doped fiber amplifier and broadband super-fluorescentsource(SFS) . This new type EDFA proved its ability of broadbandamplification in 1540nm~1610nm range under different inputconditions . And the bidirectional-pump, double-pass structure SFSbased on this novel type erbium-doped fiber demonstrated the 88nmline-width with the output power of 14.3dBm.3. Study on gain flatten techniques and experimentsBased on the investigation of the fiber loop mirror(FLM), ancascade-FLM filter was proposed and realized to flatten the gain of Cband EDFA. With this filter the gain fluctuation was reduced to ±1dBfrom ±5dB in the range of 1535nm～1557nm .4.Theoretical analysis of optical auto gain clamping(OAGC) EDFA andexperiments1) Theoretical investigated the stable and transient property ofOAGC-EDFA using computer simulation. The influence to the residualchannels induced by the variation of pump power, loop loss, add/droppower, clamping wavelength were fully considered.2) We proposed the scheme for the first time to use the FLM in thefeedback loop as filter to realized the dual-clamping EDFA. The 0.1dBgain ripple of the dual-wavelength-clamping EDFA proved the validityof this scheme.