Study Of Silicon Based Optical Switches At Mid-infrared

The research of integrated optics has extends from near-infrared to mid-infrared wavelengths in recent years. Especially researches for silicon mid-infrared optics, is a hot area in mid-infrared integrated optics. Design and production of various infrared waveguide devices compatible with CMOS technology and its advantages on the silicon wafer, shows great application potential in the mid-infrared spectroscopy, chemical sensing, environmental monitoring.Based on the contents mentioned above, we propose several kinds of mid-infrared waveguide optical switches in theory and experiment. The work of this thesis can be summarized as following:1. According to the Euler-Bernoulli beam equation in Micro Electro Mechanical Optical Systems (MEMOS), we designed a mid-infrared optical switch based on suspended directional coupler. By using electrostatic force and mechanical deformation of suspension waveguide, we can change the coupling coefficient, so as to the control of the output situation and ON/OFF states of the switch.2. We expound the experiment procedures for the desired mid-infrared suspended directional coupler. By two steps of lithography, dry etching and wet etching, the waveguide with suspension structure can be fabricated at last. Then we introduced the experiment parameters, matters need attention and specific operations, results of experiment are analyzed and suggestions for improvement are also put forward. A mid-infrared test platform is visualized at the same time.3. We designed a SPP based optical switch by using phase change materials called vanadium dioxide, which can phase change from dielectric to metal. Based on mode conversion, the designed switch can work in an ultra wide band, ranging from2to6μm, and for λ0=4μm, α-λ0-length device’s extinction rate can reach14.3dB.