Research On Broadband Gain-flattened Optical Fiber Amplifiers

Optical fiber amplifier has led to an ultimate revolution in optical fiber communications. Itis a key technology for high-speed, big-capacity telecommunication system. As gain-flatnessof optical fiber amplifier is an important parameter for Dense Wavelength DivisionMultiplexing (DWDM) system, an increasing number of people begin to research on thegain-flatness characteristic of high efficient optical fiber amplifer. There are two typicalamplification technologies, Erbium-doped Fiber Amplifier (EDFA) and Raman FiberAmplifier (RFA). This work aims to design conventional (C-band) and long (L-band) bandgain-flattened EDFA and broad-band gain-flattened RFA with the method of simulation,designing and experiment.First, the mathematic model of EDFA was built and simulated. Based on which, C-bandand L-band gain-flattened EDFAs were designed and optimized. With the designedconfiguration,20dB0.8dB flat gain and3dB NF covering C-band has been obtained.20dB1dB flat gain and3to4dB noise figure (NF) also has been got. Second, the flat gainof RFA is decided by the wavelength and power of pump lasers, so Genetic Algorithm wasused to optimize the conbine of pump lasers then1dB gain fluctuation covering1530-1605nmwas obtained. After those analyses of EDFA and RFA, a kind hybrid optical fiber amplifier ofEDFA and RFA was designed and simulated.According to the theoretical analysis of gain-flattened EDFA, an experimentalconfiguration of gain-flattened EDFA was built practically. In order to estimate the gainchanracteristic of the gain-flattened EDFA, the measurement system was set up and relatedexperiments were done using self-made tunable signal source and broadband light souce.With the development of the manufacturing technology of fibers, an increasing number ofpeople attached great importance to RFAs which used the Photonic Crystal Fibers (PCFs) asthe gain medium. It has been a new research direction of optical fiber amplifiers. In this work,a kind of high nonlinear PCFs were designed and simulated. Then a Raman Photonic CrystalFiber Amplifier which is based on the designed PCFs was built and simulated. At last,1dBsignals gain fluctuation covering C-band which used the designed Raman Photonic Crystal Fiber Amplifier was obtained.It can be believed that the research on broadband gain-flattenedEDFA and RFA will playimportant roles in the next generation telecommunication systems.