Line defects on photonic crystals for the design of all-optical power splitters and digital logic gates. (October 2017)

• Record Type: Journal Article
• Authors: Saghaei, Hamed; Zahedi, Abdulhamid; Karimzadeh, Rouhollah; Parandin, Fariborz
• Is Part Of: Superlattices and microstructures. Volume 110(2017)
• Page Start: 133
• Page End: 138
• Publication Date: 2017-10
• Subjects: Optical splitter -- Logic gates -- Photonic crystals -- Dielectric rods -- Total internal reflection; Superlattices as materials -- Periodicals; Microstructure -- Periodicals; Semiconductors -- Periodicals; Superréseaux -- Périodiques; Microstructure (Physique) -- Périodiques; Semiconducteurs -- Périodiques; 621.38152
• DOI: 10.1016/j.spmi.2017.08.052
• Languages: English
• ISSNs: 0749-6036

Abstract

Abstract: In this paper, a triangular two-dimensional photonic crystal (PhC) of silicon rods in air is presented and its photonic band diagram is calculated by plane wave method. In this structure, an optical waveguide is obtained by creating a line defect (eliminating rods) in diagonal direction of PhC. Numerical simulations based on finite difference time domain method show that when self-collimated beams undergo total internal reflection at the PhC-air interface, a total reflection of 90° occurs for the output beams. We also demonstrate that by decreasing the radius of silicon rods instead of eliminating a diagonal line, a two-channel optical splitter will be designed. In this case, incoming self-collimated beams can be divided into the reflected and transmitted beams with arbitrary power ratio by adjusting the value of their radii. Based on these results, we propose a four-channel optical splitter using four line defects. The power ratio among output channels can be controlled systematically by varying the radius of rods in the line defects. We also demonstrate that by launching two optical sources with the same intensity and 90° phase difference from both perpendicular faces of the PhC, two logic OR and XOR gates will be achieved at the output channels. These optical devices have some applications in photonic integrated circuits for controlling and steering (managing) the light as desired. Highlights: 4-channel optical splitter. Optical logic gates, OR and XOR. Optical waveguide.