Design And Research Of Multi-channel Filter Based On Two-dimensional Photonic Crystal

With the rapid development of information and communication technology in the 21 st century,there are a series of serious problems in traditional electronic communication,such as the shortage of frequency band resources,the bad electromagnetic environment and the low transmission efficiency.In order to meet the requirements of ultra-high speed information processing and mass information transmission in optical communication network,the optical interconnection technology with the advantages of low delay and loss,large band width and so on.which has been widely concerned by researchers.In the optical interconnection system,the high efficiency optical filter is an important device to realize multichannel Dense Wavelength Division Multiplexing(DWDM).which can realize the transmission,processing,acquisition and exchange of optical signals.In microwave signal processing,high-performance optical filters can usually achieve lower signal delay,larger bandwidth and stronger anti electromagnetic interference performance than traditional filters.The optical ring resonator filter based on the photonic crystal has the advantages of high transmission efficiency,flexible structure design and easy integration,which has important application value in the optical communication network.In this paper,a narrow-band photonic crystal filter with high output efficiency,compact structure and high quality factor is designed by coupling the photonic crystal waveguide and the ring resonator.First of all,Based on the electromagnetic field theory of photonic crystal,this paper introduces the numerical analysis methods used to analyze photonic crystal,including plane wave expansion(PWE)and finite element analysis method(FEM).The procedure of solving the photonic band gap by PWM is deduced in detail,and the basic idea of solving the problem by FEM is introduced.Secondly,the coupled mode theory of Photonic crystal waveguide and resonator and the basic principle of optical resonator are analyzed,which provide the theoretical basis for the later research.Thirdly,based on the coupling of photonic crystal waveguide and ring resonator,an efficient two-dimensional photonic crystal filter is designed,and the photonic crystal band gap is analyzed by PWE.The FEM is used to study the transmission characteristics of different wavelengths of light in the device,and the transmission spectrums of different ports are given.The simulation results show that the transmissivity of the filter is 97.2% at1529.3nm and the quality factor Q is 3641.The influence of the structure parameters on the output spectrum of the filter is studied.Finally,by using the hexagonal ring resonator designed in the previous chapter,the multi wavelength output of 1537.8nm,1543.7nm and 1548.7nm is realized by setting different central dielectric radius.The transmittance of the output ports is more than 90%,and the average channel spacing is only 5.5nm,and the average channel crosstalk value is-27 db.