Design And Performance Study Of Quasi-periodic Photonic Crystal Devices Based On Sunflower-type

With the continuous development of science and technology,people require semiconductor electronic devices with high transmission efficiency and large information capacity,the existing electronic transmission capacity has reached the limit,can no longer meet human needs,and the emergence of photons to solve this problem.Photon is a kind of boson with certain elasticity,its speed is constant and the exclusion is weak,and there is no interference between each other,so the ability to transmit information is very stable.In addition,photons also have unique properties such as frequency and polarization,which make their information transmission capacity greatly increased.How to utilize photons efficiently is one of the problems scientists are eager to solve.Photonic crystals are artificial microstructures with a periodic arrangement of refractive indices that have many properties similar to those of semiconductor materials.Scientists have taken advantage of these properties to build waveguides by removing dielectric columns to flexibly control the flow of light.Photonic devices designed with photonic crystals as materials have advantages over conventional electronic devices,such as flexible and compact structures and fast response times.The photonic crystal devices in this paper are all nematic quasi-periodic photonic crystals.A single-blade double-throw switch and two beam splitters with different beam splitting ratios are designed by combining this structure with the magneto-optical effect,and a photonic crystal logic gate that can realize seven logic state transitions without changing the structure is designed by combining it with QPSK signals.The details of the study are as follows:(1)A single-blade double-throw switch is designed based on a six-fold nematic quasi-periodic photonic crystal and the magneto-optical effect,and the structure is uniformly separated into three regions by constructing a three-port Y-shaped waveguide.By applying bias magnetic fields in different directions to the different regions,the unidirectional boundary modes between the different regions are coupled,and the electromagnetic waves will then be transmitted in a specific direction,which is a good realization of the single-blade double-throw switch function.Based on the eight-fold sunflower-type quasi-periodic photonic crystal and magneto-optical effect,the 1×2beam splitter and 1×3 beam splitter are designed.The total transmission rate is close to 100%,and the transmission loss is 0.01 d B.(2)A photonic crystal logic gate is designed based on a six-fold nematic quasi-periodic photonic crystal and QPSK signal.The K-type waveguide is constructed by deleting part of the dielectric column in the structure,and there are four waveguides and four ports in total.Two of them are signal input ports and two are signal output ports.The signal is output from the output port,and is determined to be a logic 1 or 0 according to the strength of the signal light at the output port.The proposed structure also has the advantages of small footprint,fast response time and simple structure.