Resonant ring modified photonic crystal high NDBP slow light waveguide, obtaining method and application

The photonic crystal waveguide has the capabilities of reducing the size of an optical device, expanding the bandwidth and controlling the group velocity dispersion effect, the slow light performance can be optimized by improving the structure of the photonic crystal line defect waveguide, and the normalized delay bandwidth product (NDBP) is a key parameter for comprehensively evaluating the slow light performance. Therefore, the resonant ring modified photonic crystal high NDBP slow light waveguide provided by the invention has relatively low group velocity dispersion and a relatively large NDBP value, and can be applied to many miniature optical cache devices. A line defect photonic crystal waveguide is constructed by removing a row of air holes in the center of the waveguide, the radiuses of the first row of air holes close to line defects are changed, and the slow light performance is optimized. And a resonant ring is introduced into the line defect waveguide, so that the flexibility and the tunability of