| The invention of fiber Raman amplifier (FRA) has brought a significant evolution to the optical communication. FRA can extend the transfers bandwidth, increase the transfers' speed and the distance without relay. The main contents of this dissertation are classified as follows:(1) The latest development of optical communication and optical amplifiers are reviewed. The recent status and trend of FRA are discussed. (2) The essential theory, Raman gain spectrum, gain characteristics, the configuration and pump sources of the FRA are analyzed. (3) The lump fiber Raman amplifiers (LRA) have been theoretically designed in detail.a). The selection of the active medium for LRA is studied. The polynomial formulas of SRS Stokes spectrum and effective core area for different fibers are got by sampling and digitized fitting. The LRA gain curves are obtained through calculating the gain for different fiber lengths and different pump power distribution. From the comparison of the fiber lengths, the pump power and the gain flatness for same gain of FRA, that DCF have been chosen as the active medium of LRA.b). The gain bandwidth and gain flatness of LRA are studied. The signal channel number of LRA is designed by calculating the gain and bandwidth of the different channel number. The optimal pump wavelength and power of FRA have been chosen by the comparison of gain flatness for different pump wavelength and the power.c). The effect of the fiber length is studied. The optimal fiber length of LRA using DCF as the active medium is obtained. The gain of LRA using SMF+DCF and DCF+SMF as the active medium is calculated.d). The saturation and transient effect of LRA, the automatic gain control technique are discussed for the optimal design of gain characteristics.e). The ASE noise, the crosstalk noise and the Rayleigh noise of LRA are studied, and the noise figure is calculated. (4) The experiment configuration of LRA and the experiment on measuring the Raman gain coefficient are discussed.
|
PDF Full Text Request