Optical Band Gap Engineering based on Single and Multiple Twin Defects Distribution inside One- dimensional Photonic Crystals

In this paper band gap tuning for one-dimensional photonic crystals by introducing single or multiple twin defects is investigated. We show that by use of the width and index of refraction of introduced defect layers the reflected and transmitted bands can be controlled. It is shown that introduced defect layers convert some part of the reflection band to transmission band. Also, we show that using multiple defects, number of peaks and holes in the reflected and transmitted signals can be controlled. In this study it is shown that distance between defects is important for band gap engineering. Also, using the proposed method, tunable optical multi-band filters can be designed that is so important for optical signal processing. The proposed technique can be realized using electro optics and all optical methods. Key words