Design Of Thermo-optical Switch Based On A Directional Coupler

With the huge increase in the amount of information exchange,the requirements for the speed,capacity,and reliability of the transmission network are increased greatly,therefore optical switches have received extensive attention.This thesis firstly introduces the research significance of optical switch,presents the classifications,the research progresses and developments of optical switches.Based on Maxwell's equations,the thermal model of thermal switches is established combined with the polymer materials suitable polymer materials were selected for the switches;finally,the design process of the thermo-optic switch is given based on the material properties.The design and the simnlation of a directional coupler type thermo-optic switch with low power consumption and low crosstalk are carried out.In this thesis,based on the brief introduction about UV-curable adhesive(Noland Optical Adhesive,NOA)and property-tailorable polymer material(Perfluorocyclobutyl,PFCB),a polymeric thermo-optic switch with directional coupler waveguide structure was designed.Using their excellent material properties and optical properties to construct the optical waveguide structure,computational simulations are performed based on the principles of thermo-optic effect and beam propagation method.Firstly the size of the thermo-optic switch is optimised to find the optimal electrode position and its size.Then the impact of various structure parameters on the switch performance is analyzed.The optimal curved waveguide is designed and Cos-Bend type is optimized.When a branch pitch is 350?m and the straight waveguides length is 1490?m for the Cos-Bend type waveguide,the switch meets the design requirements.At this time,the length of the curved waveguide is 2100?m,and the total length of the thermo-optic switch is 5870?m.Afterwards,the overall performance of the built-in thermo-optic switch is optimized to obtain the optimal structural parameter range for the thermo-optic switch,an ultra-low crosstalk of-51.6dB is reached when the switch is at room temperature;When the working temperature is 7K,the power consumption of the switch electrode is 0.743 mW,the switching time is 0.428 ms,and the crosstalk is-17.41 dB.The results show that the designed switch meets the requirements of low power consumption and low crosstalk.