Structure Parameter Optimization Ot Photonic Crystal Mach-Zehnder Interference And Research On Sensing Performance

Optical sensor is a product of interdisciplinary, which has the advantages of high safety, fast detection, easy operation and etc; moreover, it has been widely applied in many fields. Taking the advantages of forbidden band and localization of photonic crystals, we can control the propagation of photons, design outstanding performance photonic crystal sensors, and realize the real-time detection for parameters that need to be measured. Moreover, photonic crystal sensors have become a hot research in optical sensing field, due to its strengths of fast transmission speed, low energy loss, wide transmission band, strong anti-jamming capability, large information capacity, fast response speed, small volume, high integrated level, cheap price and etc. Based on the priorities of photonic crystal and the theory of waveguide transmission loss, this paper designs and optimizes the photonic crystal waveguide MZI structure and proposes photonic crystal waveguide MZI structure model, besides sensing characteristics analysis about this model also included. The main contents of this thesis are as follows:First, by using plane-wave expansion method(PWE) and finite-difference time-domain technique(FDTD), the band-gap properties of the complete photonic and transmission characteristics of defect photonic crystal are studied. Meanwhile, we proposed photonic crystal waveguide MZI structure model and also analyze its transmission characteristics. Furthermore, the transmission loss of photonic crystal’s straight waveguide and bend waveguide are also analyzed on the basis of theory and simulation, so that photonic crystal waveguide MZI structure’s transmission loss is available to be analyzed.Next, based on FDTD, we carry out numerical simulation for photonic crystal waveguide MZI’s transmission characteristics, and train BP neural networks. Then by using trained BP neural networks, we optimize photonic crystal MZI structure parameter, which can help us get the maximal normalized transmission rate and eventually achieve overall optimization of air-filling fraction.Finally, according to the optimized photonic crystal waveguide MZI model, wedesigned single-arm notching structure double-arm notching. Besides we separately study the theory of these two different sensors and take contrastive analysis to know their respective sensing property, eventually we find the better photonic crystal waveguide MZI sensor.