The optimal design of photonic crystal optical devices with step-wise linear refractive index

•In the paper, we have studied one-dimensional step-wise linear photonic crystal.•We have analyzed the effect of defect layer parameters on the transmissivity.•We have calculated the electric field distribution and the output electric field.•We have obtained optimal parameters, which can optimally design optical device.

In the paper, we have studied one-dimensional step-wise linear photonic crystal with and without defect layer, and analyzed the effect of defect layer position, thickness, refractive index real part and imaginary part on the transmissivity, electric field distribution and output electric field intensity. By calculation, we have obtained a set of optimal parameters, which can be optimally designed optical device, such as optical amplifier, attenuator, optical diode by the step-wise linear photonic crystal.