| Summary: | 碩士 === 國立臺灣科技大學 === 光電工程研究所 === 99 === This thesis focuses on the study of bi-directional fiber amplifiers in single-wavelength pumping mechanism. The improvement of pump power efficiency by reusing the residual pump power is also investigated. There are three parts in this thesis. For the first part, the C+L band bi-directional erbium-doped fiber amplifiers (EDFAs) are introduced. A single-wavelength pump laser is pump-sharing to the C+L band fiber amplifiers by appropriately adjusting the pump power ratio, with 30% to the C band EDFA and 70% for the L band EDFA, respectively. Then, a 99% reflectance fiber-Bragg-grating (FBG)-based pump reflector is used to recycle the residual pump power for the C band EDFA.
The second part discusses bidirectional hybrid amplifiers in recycling-pumped mechanism, where the C band and L band are EDFA and Raman fiber amplifier (RFA), respectively. The hybrid fiber amplifiers, in parallel structure, may reduce the possible attenuation of C band EDFA to the L band wavelength division multiplexing (WDM) channels and vice versa. In our example, all the pump power is provided for Raman amplification, then 54.88 mW residual pump power is reflected by a pump reflector. It can reflect 38% of pump power to the RFA while the other 62% (i.e., 100%-38%) to the C band EDFA. Note that 38% reflectance is selected as it could minimize the gain variation between the C band EDFA and L band RFA under the condition of -20 dBm input power per channel.
The third part of the thesis is to verify the bi-directional fiber amplifiers in 50- and 75 km point to point scheme. For the C+L band hybrid fiber amplifier, we find that the BER performance is much worse for the C band EDFA than the L band RFA. It may be due to the lack of chromatic dispersion compensation. Nevertheless, it could be compensated easily using 11 km DCF. In summary, the proposed bi-directional C+L band EDFAs and C+L band hybrid fiber amplifiers have the advantages of residual pump power recycling and low-power penalty. It may find vast applications in optical communication and WDM system.
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