Studies On Er/Yb-codoped Phosphate Ion-exchanged Channel Waveguide Amplifier

This dissertation presents a detailed data analysis study firstly to the best of our knowledge, on the physical process of analysis work of Er³⁺/Yb³⁺ codoped waveguide amplifier of phosphate glass using eight energy levels model.In the dissertation, small signal's amplified character of 1530nm wavelength in Er³⁺/Yb³⁺ codoped phosphate glass waveguide amplifier pumped by 980nm light was dynamically simulated in details. Compared with the results reported, we decided to adopt the eight energy levels model of Er³⁺/Yb³⁺ codoped waveguide amplifier, which is composed of rate equation and transfer equation of pump power and small signal power. Rate equation includes eight energy levels of Er³⁺ and Yb³⁺, and considering the procedure of exited stated absorption, upconversions between Er³⁺ ions and energy transfer between Er³⁺ and Yb³⁺ ions. We applied numeric analysis to solve the theory model; after the waveguide was uniform discretization along the transfer direction, rate equations, the overlap intergration between the mode fields distribution of pump and signal light and the popution density to the cross-section of the waveguide and transfer equations of pump power and small signal power were solved by adopting least square method, Simpson method and Runge-Kutta method respectively.On the base of the work completed, we have finished the following researches. The eight energy levels model has to be adpoted compared results of the eight energy levels and the simplified five energy levels. Basing on the eight energy levels model, the realation ship between the gain and the pump power, the doped concentration, and the waveguide length at 1530nm are received. At the same time, the evolution character of the pump power along the axis of the waveguide and the distribution character of the popution density and the popution bave been researched. Besides, ion-exchange method was studied, now methods of Ag⁺ exchanges with Na⁺, K⁺ exchanges with Na⁺, K⁺ ,Ag⁺ mixing exchanges with Na⁺, K⁺ ,Ag⁺, Na⁺ mixing exchanges with Na⁺ are used to fabricate Er³⁺/Yb³⁺ codoped phosphate waveguide. Ion-exchange can be expressed as follows: A_molten+B_substrate (?) A_substrate +B_molten, the buried waveguide can be fabricated using appied electric fields in the process, then the damage to the surface of the waveguide from the ion-exchange is conquered, the loss of the waveguide is reduced, and the waveguide and the fiber can couple well.