The characteristics of high-order Bragg waveguide grating based on phase-mask method are investigated,and the resonant wavelengths of Bragg waveguide grating with different orders all increase with the increasing of saturation coefficient.Influences of the order of grating,diffraction efficiency of phase mask and saturation coefficient on the refractive index modulation of Bragg waveguide grating are taken into consideration synthetically.The largest refractive index modulation amplitude can be acquired whe...