B型抗諧振反射光波導(ARROW-B)結構之光子晶體波導研究

Abstract

本研究探討B型抗諧振反射式光波導結構之光子晶體波導元件。B型抗諧振反射式光波導結構可傳輸橫向電場偏極化(TE)及橫向磁場偏極化(TM)的基模光，且具有較大的導光區可有效和單模光纖耦合。而B型抗諧振反射式光子晶體光波導中，若使光操作在光子晶體之完全能隙中，可同時有效率的傳輸橫向電場偏極化(TE)及橫向磁場偏極化(TM)的基模光，其垂直方向利用抗諧振反射式光波導結構導波，而水平方向則是利用光子晶體能隙導波原理。我們使用套裝軟體FULLWAVE，以平面波展開法(PWM)分析光子晶體能帶；有限差分時域分析法(FDTD)來模擬光在二維光子晶體波導中波的傳輸，以此得到最佳的平面結構參數，再利用FDTD模擬B型抗諧振反射式光子晶體光波導中波的傳播行為，模擬結果顯示在三角形結構中傳輸橫向磁場偏極化(TM)及橫向橫向電場偏極化(TE)可分別達到92.1%(0.357-dB loss)及89.7%(0.472-dB loss)，而在四方形結構中則分別為88.1%(0.550-dB loss)及86.1%(0.649-dB loss)。

In this research, we investigate the ARROW-B photonic crystal waveguide. The ARROW-B structure can guide light in the fundamental modes of TE and TM polarization, and provides a large core size compatible to single-mode fibers. An ARROW-B photonic crystal line defect waveguide can guide TE and TM modes simultaneously with a photonic crystal structure in the horizontal direction and an ARROW-B structure in the vertical direction. We use the plane wave expansion method (PWM) with a commercial software “FULLWAVE” to analyze the band structure in a 2D photonic crystal and use the finite difference time domain (FDTD) method to simulate the transmission of wave in a 2D PC waveguide to determine the optimal parameter of the lateral structure. We also use FDTD to simulate wave transmission in an ARROW-B PC line defect waveguide. The results show that high transmission of approximately 92.1% (0.357-dB loss) and 89.7% (0.472-dB-loss) for TM and TE, respectively, can be achieved simultaneously in the triangular ARROW-B-based PC waveguide if operating in the complete band gap. And in the square ARROW-B-based PC waveguide, the transmission value are approximately 88.1% (0.550-dB loss) and 86.1% (0.649-dB loss) for TM and TE mode, respectively.