Power-loss Analysis of Transitional Waveguide Based on Finite-Difference Beam Propagation Method

In order to minimize the powerloss grade waveguide and band waveguide without increasing the dimension, four shape functions of transitional waveguide are proposed and analysed by the finitedifference beam propagation method. Based on it, conditional relations between optimized transitional waveguide shape and the angle of transitional waveguide are found out and expressed in math formula.