Research On Key Technology Of Integrated Optical Waveguide Delay Line

With the development of the information society,the amount of people's information exchanges is increasing every day,so the requirements for the capacity,speed,and reliability of the transmission network are constantly increasing.Compared with electrical signals,optical signals have a faster transmission rate and are highly resistant to electromagnetic interference.The rapid development of integrated optics has also shown a trend to replace traditional electricity in all aspects.The integrated optical waveguide delay line is an important link in optical signal processing,and its key technology optical switch has also received widespread attention.This paper mainly conducts the research on the integrated optical waveguide delay line based on MZI thermo-optical switch.Through the analysis of the heat distribution in the waveguide,the design and optimization of the structure are realized,the related performance of the device is improved,and the technical reference for related applications is provided.This paper selects the silicon dioxide-based integrated optical waveguide delay line as the research object,and the completed work includes:(1)Choose a silica waveguide material with a refractive index difference of 0.75%,based on the single-mode conditions in the design theory,combined with the maximum transmission depth,determine the cross-sectional size of the rectangular waveguide during single-mode transmission;then the waveguide mode coupling theory will be used for correlation Derive,obtain the relationship curve between coupling distance and coupling length,and make a reasonable selection;by establishing a corresponding simulation model,verify and select the single-mode transmission size with the help of Mode Solution,and combine the equivalent coupling effect existing in S-bend to complete the coupling length And the optimized design of the S-bend part,and finally completed the design of the 3d B coupler.(2)Using Comsol software based on the finite element method(FEM),combined with the temperature propagation equation,the corresponding modeling work is completed,and the temperature distribution in the waveguide is simulated and analyzed;the electrode length is determined by the temperature change and the device stability;The influence of different electrode positions and sizes,and the thickness of the upper and lower cladding layers on the temperature distribution of the waveguide in a single waveguide;the influence of the thickness of the lower cladding layer and the width of the air groove on the temperature distribution in the waveguide in the case of dual waveguides.The MZI thermo-optical switch is preliminarily determined based on the thermo-optical effect of the material After the size,the function verification and parameter test of the switch were carried out,and the S-bend part was optimized to complete the improvement of the loss and extinction ratio parameters of the MZI thermo-optical switch;finally,the different substrate materials and whether the air groove structure is adopted MZI thermooptical switch has carried out the simulation analysis of the switching speed.(3)The distance between adjacent optical switches and the minimum bending radius of the curved waveguide are determined by simulation,and the design of the 4-bit integrated optical waveguide delay line based on the MZI thermo-optical switch is completed.The refractive index difference of the silica rectangular waveguide is 0.75%,the height and width of the core layer are 5.5?m,the size of the upper cladding layer and the left and right cladding layers are 5?m,the thickness of the bottom cladding layer is6?m,the electrode length is 1mm,the width is 15.5?m,single MZI The power consumption of the thermo-optical switch is 96.7m W,the on time is 74?s,and the off time is 135?s;the delay line can achieve a total of 16 delay states from 0 to 45 ps,with a step of 3ps,the minimum power consumption is 96.7m W,and the maximum power consumption It is 483.5m W,the overall size is 10.9mm×29.6mm,and the minimum bending radius is 5mm.