Study on the diffraction performance of the etched blazed grating

The diffraction properties of a silica-based etched diffraction grating are investigated by numerical simulation in three-dimension. The field distribution of the electromagnetic filed in the near and far away groove area, the diffraction efficiency and spectral response of 8 channels are analyzed respectively. The numerical results show that the diffraction angle is not satisfied the famous grating formula, the deviation of the diffraction angle is increasing with the diffraction order. And when the groove depth is in the low and medium modulation region, the diffraction efficiency reaches over 90%, and the spectral response of an etched grating is uniform within the fiber communication spectrum range.