Study On The Polarization-Dependent Gain And The Laser Diode Driver For The Fiber Raman Amplifier

Fiber Raman amplifier(FRA), as one of the key parts in the next DWDMsystem, has advantages such as high gain and saturated output power, low noise, widebandwidth. Recently, FRA has been the focus of the research in opticalcommunication. The main contents of this dissertation are classified as follows:(1) The latest development of optical communication and optical amplifiers isreviewed. The recent domestic and foreign status and trend of FRA are discussed.(2) The essential theory and structure, including stimulated Raman scattering,Raman gain coefficient and threshold, gain and noise characteristics, theconfiguration and pump sources of the FRA are analyzed.(3) The theory and the design of experiment configuration on reducingPolarization-Dependent Gain (PDG) in FRA are discussed. As for the depolarizerusing Polarization Maintaining Fiber (PMF), some important parameters which affectthe depolarization result are studied. The length and the beat length of the PMF, theangle of the two PMF's principle axes and the spectral half-width are calculated.(4) The driver based on the prototype digital driver, used for six laser diodes(LD), is designed. Its control ways are digital and analog mixture. The main contentsare the LD characteristic, the whole design of the driver, the design principle of thepartial circuit, the interface between the people and the instrument, and the test resultof the driver's property.