MULTILAYER OPTICAL BANDPASS FILTER Russian patent published in 2015 - IPC G02B5/28 

FIELD: physics.

SUBSTANCE: filter comprises a dielectric substrate coated with thin-film layers of dielectric materials with alternating high refraction index n_H and low refraction index n_L. Part of the layers of the material with refraction index n_L is resonators having electrical thickness π at the centre frequency of the transmission band. All of the other layers form multilayer dielectric mirrors which separate each resonator from the adjacent resonator, the dielectric substrate or outer space. In each i-th mirror, the electrical thickness θ_Li of layers with refraction index n_L is less than π/2, and the electrical thickness θ_Hi of layers with refraction index n_H is greater than π/2 by Δθ_Hi and 2Δθ_Hi for outer and inner layers, respectively, where the values θ_Li and Δθ_Hi satisfy the equation .

EFFECT: providing virtually any required bandwidth with virtually any non-uniformity of the light transmission coefficient in said bandwidth.

2 dwg, 1 tbl