OPTICAL FILTER, AND OPTICAL MIMO COMMUNICATION SYSTEM USING THE SAME

摘要

PROBLEM TO BE SOLVED: To achieve a transmitting angle filter when an angle of incidence falls within a prescribed angle.;SOLUTION: An optical filter is composed of a dielectric multi-layer having a low refractive index layer 1 and a high refractive index layer 2 alternately laminated. In a host area 10, refractive indexes and thicknesses of the high refractive index layer 2 and the low refractive index layer 1 are set so that a line of an angular frequency serving as a design wavelength λ passes through a low end of a propagation band when k_y is 0 in a dispersion characteristic indicative of a relation between k_y and the angular frequency. Antireflection areas 11 and 12 are set so that equivalent transverse impedance and the number of laminated layers are prescribed values. Further, the thickness of the high refractive index layer 2 or the low refractive index layer 1 contacting with air of the antireflection areas 11 and 12 is set so that transverse impedance at an interface between the host area 10 and the antireflection areas 11 and 12 and transverse impedance at an end surface of the antireflection area agree with each other, and its imaginary part is 0.;SELECTED DRAWING: Figure 1;COPYRIGHT: (C)2017,JPO&INPIT