Study On Gain Flattened Erbium Ytterbium Co-Doped Double Clad Fiber Amplifier

Optical fiber amplifier is widely used in various fields because of its small size,simple structure and high stability.The history of optical fiber amplifier shows that the current research is advancing in two directions.On the one hand,it improves the integration of the amplifier by reducing the cost and reducing the volume,so as to meet the specific requirements in different environments;on the other hand,innovative optical technology and optimized design scheme improve the performance of fiber amplifier,including higher power,lower noise and stronger stability.Firstly,this paper briefly introduces the development process and application of optical fiber amplifier,and summarizes the scientific research results and data of gain flattened optical fiber amplifier at home and abroad.Then the working principle of fiber amplifier is described,the characteristics of Erbium-Ytterbium co-doped fiber are briefly described,and the rate equation and transmission equation of Erbium-Ytterbium co-doped fiber amplifier(EYDFA)are given.The main idea of the simulation experiment is that the signal light is output after two-stage amplification.By changing the signal wavelength and signal power,the influencing factors and output characteristics of fiber amplifier are explored,and the gain fiber length suitable for the experiment is selected.Finally,the laser output with flat gain in the wavelength range of 1535-1575 nm is completed,which plays a guiding role in specific experiments.The simulation results guide the experiment,and a set of EYDFA based on main oscillation power amplification(MOPA)structure is completed.The gain medium of pre amplification stage is 13 m Erbium-doped fiber,and the gain medium of main power amplification stage is 7m Erbium-Ytterbium co-doped double clad fiber.During the experiment,the system uses a tunable light source to input 10 m W laser as the signal light,and realizes the gain flat laser output in the band of 1535-1575 nm after two-stage amplification.The gain flatness is ±0.32 d B,and there is no obvious amplified spontaneous emission(ASE).When the primary pump power is 500 m W and the secondary pump current is 5A,the laser output with the highest power of 1.428 W at the central wavelength of1555 nm is realized.