Research Of All-optical Logic Gate Based On The Self Collimation Effect Of 2D Photonic Crystal

All-optical networks have tremendous advantages over traditional electronic technologies.One of the key components is the all-optical logic gate.In recent years all-optical logic gates have been reported in a number of papers.These gates can perform a variety of functions and draw a lot of attention.However,they have some drawbacks such as low speed,complex structure and large size.Recently,all-optical gates based on two dimensional(2D)photonic crystals(PCs)have been proposed.All-optical logic gates based on PCs could be designed by the third-order nonlinear optical effect,the multi-mode interference effect,the self-collimation effect and the resonances of cavity.The self-collimation effect has a significant potential for the realisation of various applications.The self-collimation effect is a manifestation of an anomalous dispersion in PCs.A self-collimattion beam can be transmitted along the straight line in diffractionless PCs,similarly to a photonic crystal waveguide.In this paper,we used the self-collimation effect in PCs and the interference principle in traditional optics to design six all-optical logic gates,which are NOR gate,NAND gate,XNOR gate,NOT gate,OR gate and AND gate.All six all-optical logic gates are realized by constructing line defects in photonic crystals.They have features such as simple structure,small size,and high contrast.In particular,the current research on NOR gates.NAND gates and XNOR gates is relatively small.Most of the proposed schemes are relatively complex,with a single logic function,slow response speeds and so on.This paper proposes a simpler structure for NOR gates,NAND gates and XNOR gates and optimizes them to effectively reduce the size of device and achieve efficiently transmit signals.The logic function is more excellent.The main contents of this paper are as follows:1.A novel beam splitter based on self-collimation effect is proposed.The beam splitter is a line defect produced by a row of rods in the PC with self-collimation effects.The structure of the beam splitter is simple and the beam splitting is efficient.Adjusting the radius of the line defect can change the splitting ratio,and under certain conditions,the reflectivity and transmissivity of the beamsplitter are determined.In this paper,the proposed total reflection is a superposition of multiple line defects,and analyzes the performance of total reflection under different conditions.The radii and numbers of the line defects are respectively changed to simulate and analyze the data of the total reflection.According to the simulation results,finally select six rows of line defects as a total reflection.2.In this paper,three new all-optical logic gates based on self-collimation of two-dimensional photonic crystals are proposed.They are NOR gates.NAND gates,XNOR gates,NOT gate,OR gate and AND gate respectively.The six all-optical logic gates consists of beam splitter and total reflection.At the same time,we use the interference in classical optics to design logic gates.We control the output byadjusting the phase difference to achieve constructive or destructive interference as logic 1 or logic 0.By changing the distance between beamsplitters and the radius of line defect,a large number of field distributions are simulated.According to the results of data analysis,the values of each parameter are determined.3.We propose an optimized scheme for the designed all-optical logic gate.The program is achieved through the degenerate input port,two beams of signal light input from the same port.This scheme can effectively reduce devices size and reduce errors,but also reduce the complexity of devices and the difficulty of preparation.Since only one total reflection and one beam splitter,the logic gate is smaller in size,more suitable for optical integration development.