Method for designing one-dimensional photonic crystal filter based on digital signal processing

Abstract

The invention discloses a method for designing a one-dimensional photonic crystal filter based on digital signal processing. The method for designing the one-dimensional photonic crystal filter comprises the following steps that (1), the target filtering reflection spectrum of the one-dimensional photonic crystal filter is designed by utilizing the digital signal processing, the optimal expression coefficient of the target filtering reflection spectrum in a numeric field is calculated, and the optimal expression of the target filtering reflection spectrum in the numeric field is obtained; (2), a layer peeling algorithm is adopted to calculate the interface reflection coefficients of the dielectric layers of the one-dimensional photonic crystal filter; (3) the refractive indexes of the dielectric layers of the one-dimensional photonic crystal filter are calculated according to the interface reflection coefficients, obtained in the second step, of the dielectric layers of the one-dimensional photonic crystal filter. The method for designing the one-dimensional photonic crystal filter directly calculates and obtains the refractive indexes of the dielectric layers of the needed one-dimensional photonic crystal filter according to the needed filtering spectrum based on the filtering spectrum, and has the advantage of being simple and direct in calculation, the optimal expression of the target filtering reflection spectrum in the numeric field can be conveniently obtained, and therefore the one-dimensional photonic crystal filter obtained through designing is excellent in filtering performance.

Description

technical field [0001] The invention relates to a design method of a one-dimensional photonic crystal filter based on digital signal processing. Background technique [0002] In 1987, Yablonovitch and John first proposed the concept of photonic crystals. After that, photonic crystals quickly became a very active research topic in the frontier of optics, and they have important potential applications in filtering, nonlinear and other aspects. One-dimensional photonic crystals are similar in structure to optical multilayer dielectric films, that is, they are composed of dielectric film layers of different refractive index materials and thicknesses arranged in sequence. like figure 1 It is a schematic diagram of a one-dimensional photonic crystal structure composed of N layers of media, in which the refractive index of each media layer is n 1 , n 2 , n 3 , n 4 ,??,n N ; Thickness is d in turn 1 , d 2 , d 3 , d 4 ??, d N ; The reflection coefficient of the medium laye...

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Problems solved by technology

In other words, the existing prior art uses indirect methods to design one-dimensional photonic crystal filters, rather than directly design the specific structure and each structure of the photonic crystal filter based on the required spectral transmittance response. parameters, so the existing prior art design is complex

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