Effects of tilted angle of Bragg facets on the performance of successive strips based Bragg concave diffraction grating

The effects of the tilted angle of facets on the diffraction orders, diffraction spectra, dispersion power, and the neighbor channel crosstalk of successive etching strips based Bragg concave diffraction grating (Bragg-CDG) are studied in this paper. The electric field distribution and diffraction spectra of four Bragg-CDGs with different tilted angles are calculated by numerical simulations. With the reflection condition of Bragg facets constant, the blazing order cannot change with the titled angle. As the tilted angle increases, the number of diffraction orders of Bragg-CDG will decrease, thereby concentrating more energy on the blazing order and improving the uniformity of diffraction spectra. In addition, the dispersion power of Bragg-CDG can be improved and the neighbor channel crosstalk of devices can be reduced by increasing the tilted angle. This work is beneficial to optimize the performance of Bragg-CDG.