微环谐振器传输特性分析

Transmission Characteristics of Microring Resonator

主要研究微环谐振器的基本结构参数对传输特性和微环性能的影响。根据耦合模理论,给出了微环谐振器传输函数的表达式;用传输矩阵法对直波导和弯曲波导之间的耦合进行了分析,研究了耦合系数与微环结构参数之间的关系;利用时域有限差分法对微环谐振器进行数值仿真,得到其频谱响应曲线。通过分析可以得到:波导间距的增大使振幅耦合比率减小;微环半径变小,微环的弯曲损耗就会变大,品质因子变大,自由光谱范围就会变大。相对微环半径,波导厚度对微环的性能参数影响较小。在设计时,应按照实际需求来设计间距和微环半径的大小。

The main work of this paper is to research the relationship between the structure parameters and transmission characteristics, performance. The intensity transfer function of microring resonator throughput port and drop port by using the coupled mode theory of waveguides is deduced. The coupling coefficient between the bent waveguide and the straight waveguide is analyzed, using transfer-matrix method. And the relationship between the coupling coefficient and the structure parameters are discussed. Then the frequency spectrum is gotten by using FDTD simulations. The results show that amplitude coupling ration k is reducing while the gaps between microring and bus waveguides is increasing. The bending radiation loss, quality factor （ Q ） and the free spectral range （FSR） are increasing, while the radius of microring is reducing. The width of waveguide relatively has a smaller influence on the performance. So the gaps and the radius should be designed according to the needs.