Study of the resonant behaviour of waveguide gratings: increasing the angular tolerance of guided-mode filters

This paper is devoted to the study of resonant waveguide grating filters. It is shown that doubly periodic structures permit one to increase the angular tolerance of the filters without modifying the frequency linewidth. A theoretical study of such structures is presented and their response to an incident Gaussian beam is analysed. It is also shown that doubly periodic structures can be used to reduce absorption losses.