Waveguide resonators with combined Bragg reflectors

We present a method to improve the selective properties of a waveguide resonator with Bragg reflectors on both ends, a passive device that is widely used in microwave engineering and optoelectronics. It is shown that additional mode conversions lead to a significantly rarefied spectrum of eigenoscillations with different transverse field structures. In particular, this can be achieved by using doubly periodic Bragg reflectors with different azimuthal symmetries forming four wave resonant field structures. The analysis of dispersion properties presented is applicable for resonators of arbitrary relation of lengths of the reflectors and waveguide.