The reflection and transmission coefficients of the design structure is obtained based on sampled fiber Bragg grating

transfer matrix theory

a new type of photonic crystals with two different dielectric constants of materials arranged alternately periodic structure

and the theory of sampled fiber grating transmission.Simulation analysis and test results show that the design of photonic crystal structure appeared multiple reflection peak.The increase of grating length will increase the reflectivity and reflection peak number obviously without changing the reflection peak.The results also show that the bandwidth is increased obviously with larger modulation depth.With the increase of refraction index modulation

the peaks will also increase

and reflectivity is increased significantly（10%）.