Study And Design Of Polymer Waveguide Bragg Gratings With Broad Wavelength-tuning Range

In this dissertation, the polymer waveguide Bragg grating with the center wavelength near 1550 nm is discussed. Waveguide Bragg grating is one of the most important devices in the field of integrated optics.The sidewall-corrugated waveguide Bragg grating is studied.Based on Effective Index Method, Mode Coupling Theory and Transfer Matrix Method, the three-order sidewall-corrugated waveguide Bragg grating is studied and simulatd. The transmission characteristics are discussed, including: the design of single mode polymer waveguide; the optimization of structure parameters; the reduction of side-lobe influence using the apodization modulation; the research of the polarization-dependent characteristics.Combined with the high thermal coefficient of the polymer material, a thermo-optical tunable function is achieved. Further, the improved structure is proposed: first, the heating scheme is optimized to improve the heating temperature of the waveguide region. Second, the air trenches are introduced beside the core layer symmetrically to reduce the heat consumption of the electrode. The final optimized structure with strong heated, high temperature uniform and low thermal crosstalk, therefore, has a broad wavelength-tuning range.To investigate the propagation of electromagnetic fields in large scale photonic devices, an efficient wavelet-based finite-difference time-domain(FDTD) numerical model is established and parallelized in computer cluster. Compared to the standard FDTD method, this model features higher numerical dispersion properties. Thus, a significant reduction in the number of spatial cells, i.e. used memory, and a considerable decrease in the run time are achieved in the parallel computation environment. Further, the main factors that influence the parallel computation efficiency of the parallelized FDTD model is demonstrated; a mathematical model is also given to estimate the run time of the computation.