Study On Er³⁺/Yb³⁺ Co-doped Fiber Amplifier

Fiber Amplifier is one of the key components to realize all optical fibercommunication system. Erbium-doped fiber amplifier is applied widely just now. ButErbium-doped fiber amplifier can not provide adequate pump Absorption via short fiber,the structure is very complex because of the long gain fiber, and the efficiency is verylow. Doping Yb³⁺ in Erbium-doped fiber is an effective method. Yb³⁺ has bigger peakvalue absorption section (800～1100 nm), it can offer higher gain, so in this way theefficiency and gain stability of the amplifier can be improved greatly. Considering thatthe ytterbium ion works only as a tool to transfer energy, the superior characteristic ofErbium-doped fiber amplifier, such as: higher gain, lower noise, bigger output power,wider working frequency spectrum, less insertion loss and 1550nm workingwavelength-the low loss area of fiber is reserved.The influence of concentration and ratio of rare-earth on spectrum properties offiber are focused on, Absorption of the EDF's is affected by erbium concentration andratio of erbium and ytterbium. Absorption band is broadened by adding dopant ofytterbium. The effects of concentration of erbium and ytterbium ions,pump power,signal power and fiber length on the gain characteristics of the co-doped fiber amplifierare analyzed. Comparison with singly erbium-doped fiber amplifier is made,the resultof which shows that the gain and pump efficiency of Er³⁺/ Yb³⁺ co-doped fiber areapparentlyhigher than that of singlyerbium-doped fiber.The simulation and research of Er³⁺/Yb³⁺co-doped fiber amplifier is carrying inexperiment. Using the Er³⁺/Yb³⁺co-doped double cladding fiber , the pumping resourcewavelength is 980nm, the maximum pumping power coupling into inner cladding is1.33 W. The output laser wavelength is 1550 nm, and the maximum output laser is380mW with slope efficiencyis 35.41%.