Er-yb Co-doped Phosphate Glass Fiber Characteristics Analysis And Design

In this paper, Er doped fiber amplifier (EDFA) is introduced. The characteristic of EDFA areanalyzed. EDFA has two disadvantages: the gain and output power are low. So the Er/Yb co-dopedphosphate glass fiber and double cladding structure are introduced to solve these two problems. Inthis paper theory of Er/Yb co-doped phosphate glass fiber and double cladding structures arestudied. These works include three aspects: First, the basic theories of Er/Yb co-doped phosphateglass fiber are introduced, the structure of power levels of Er and Er/Yb co-doped system and thecharacteristics of spectrum of Er doped phosphate glass. Second, the gain characteristics ofEYCDFA (Er/Yb co-doped fiber amplifier) in phosphate glass substrate areinvestigated by solving numerically propagation equations and rate equations. Theeffects of Er concentration, pump power, the wave length of signal light and length offiber on the gain of Er/Yb co-doped phosphate glass fiber are discussed particularly.Finally the efficiency of pump power absorption of double cladding structure fiber isstudied particularly. Basic hypothesis of double cladding are introduced. Then twokind of circle double cladding structure are studied. The relationship betweenefficiency of pump power absorption and double cladding structure is given. Squaredouble cladding structure has higher efficiency than circle double cladding structure.In this paper, based on reasonable hypothesis, carefully designed model and numericalcalculation, theory of square double cladding structure are particularly studied. Andthe relationship between efficiency of pump power absorption and square doublecladding structure is given.Based on the study of theories, Er/Yb co-doped phosphate fiber is carefully contrived. Inorder to get higher gain and larger output power, the ingredient of host material and techniques ofphosphate glass are designed. The concentration and proportion of Er/Yb ions are given. Based onour theories of square double cladding structure, the structure of square double cladding is alsodevised. Finally the techniques of phosphate glass fiber are studied. The processes of facture areanalyzed and some possible problems are introduced. The samples of this project are made by 209institute. By on the optical stick is finished.