Research About Acousto-Optical Mach-Zehnder Structure With Multiple Arms On Silicon Optical Waveguide

With the advance of the big data era and rapid growth of data center traffic,traditional copper transmission cannot meet the needs of future development,which urgently needs higher speed.Silicon photonics with large bandwidth has become one of the inevitable trends for future development,which can be fabricated by microelectronics technology.It is very promising to solve the electronic bottleneck problem encountered by current electronic systems.In silicon photonics,it is crucial to control the optical transmission in the optical waveguide.There are many methods to control the optics in the optical waveguide.Compared with the conventional control using electro-optical and thermo-optical effects,the control based on acousto-optical effect show high extinction ratio,low driving power,and flexible design,which is a very good choice for silicon photonics to control optics.However,silicon optical waveguides do not have a piezoelectric effect.In this thesis,an improved structure is provided for the generation and transmission of surface acoustic waves on silicon optical waveguides.Based on the improved silicon optical waveguide,an optical structure on the Mach-Zehnder(MZ)structure is presented,in which,a beam of surface acoustic waves is used to modulate multiple interference arms simultaneously,it can improve the acousto-optical modulation efficiency exponentially.The content of the thesis includes:(1)Based on COMSOL software,the structural model,structural boundary conditions,electrical boundary conditions and meshing of the structure of surface acoustic waves are studied.The surface acoustic wave simulation model is established.The frequency characteristics of the surface acoustic wave and the structural stress distribution are analyzed.(2)Based on the traditional silicon optical waveguide structure for transmitting surface acoustic wave,an improved silicon optical waveguide of structure that generates and transmits surface acoustic waves with high efficiency is proposed.Compared with the traditional structure,the improved structure greatly improves the surface acoustic wave effect on the silicon optical waveguide.Also,the structural design parameter of the improved silicon optical waveguide,including the width of the optical waveguide,the number of interdigitated electrodes,the voltage of the interdigitated electrodes,and the thickness of the piezoelectric material are discussed.(3)Based on the improved silicon optical waveguide structure,an optical MZ structure is provided using multiple interference arms by single SAW.Based on the MZ structure theory,the theoretical anlaysis is discussed for the silicon waveguide acousto-optical MZ structure using multiple interference arms.The MZ structure of single-arm and double-arm by SAW modulation is compared and analyzed,and the effect of the static phase difference on the structure of single-arm and double-arm by SAW modulation is discussed.The waveguide acousto-optical MZ structure with the arms of 4,6,and 8 modulated by SAW is studied.The results show that a beam of surface acoustic waves can simultaneously modulate multiple arms,which can improve the modulation efficiency.