The effect of defect layer on transmissivity and light field distribution in general function photonic crystals

•When the defect layer moves behind, the transmission intensity of defect model decreases.•When the refractive indexes of defect layer increase, the intensity of defect model decreases.•When the refractive indexes of defect layer increase, the relative intensity of electric field was enhanced.•When the period number increases, the relative intensity of electric field increases.•The position of defect layer has the effects on the electric field.

We have theoretically investigated a general function photonic crystals (GFPCs) with defect layer, and choose the line refractive index function for two mediums A and B, and analyze the effect of defect layer's position, refractive indexes, period numbers and optical thickness on the transmission intensity and the electric field distribution. We obtain some new characters that are different from the conventional PCs, which should be helpful in the design of photonic crystals.