One-dimensional photonic crystal filter design method 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 steps of the design method are as follows: (1) Utilize digital signal processing to design the target filter reflection spectrum of the one-dimensional photonic crystal filter, and calculate the target filter The optimal expression coefficient of the reflection spectrum in the digital domain is obtained to obtain the optimal expression of the target filter reflection spectrum in the digital domain; (2), using the peeling algorithm, calculate the reflection of each medium layer interface of the one-dimensional photonic crystal filter coefficient; (3), calculate the refractive index of each layer medium of the one-dimensional photonic crystal filter according to the interface reflection coefficient of each medium layer of the one-dimensional photonic crystal filter calculated in step (2). This design method starts from the filter spectrum and directly calculates the refractive index of each layer of the required one-dimensional photonic crystal filter according to the required filter spectrum. It has the characteristics of simple and direct calculation, and can easily obtain the target filter reflection spectrum in The optimal expression in the digital domain, so the designed one-dimensional photonic crystal filter has excellent 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 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 layer i...

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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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