Modeling of graded index waveguide fabricated by ion exchange on Er3+ doped glass

A general numerical tool, based on thermal diffusion equation andfull-vectorial eigen-mode equation, has been presented for thesystematic analysis of graded index channel waveguide fabricated byion exchange on Er³⁺ doped glass. Finite difference methodwith full-vectorial formulation (FV-FDM) is applied to solving thefull-vectorial modes of graded index channel waveguide for the firsttime. The coupled difference equations based on magnetic fields inFV-FDM are derived from the Taylor series expansion and accurateformulation of boundary conditions. Hybrid nature of vectorialguided modes for both pump (980 nm) and signal light (1550 nm) aredemonstrated by the simulation. Results show that the fabricationparameters of ion exchange, such as channel opening width and timeratio of second step to first step in ion exchange, have largeinfluence on the properties of waveguide. By optimizing thefabrication parameters, maintenance of monomode for signal light andimprovement of the gain dynamics can be achieved in Er³⁺doped waveguide amplifier (EDWA) fabricated by ion exchangetechnique. This theoretical model is significant for the design andfabrication of EDWA with ion exchange technique. Furthermore, asingle polarization EDWA, which operates at wavelength from 1528 nmto 1541 nm for HE polarization, is numerically designed.