Xiao Rulei, Shi Yuechun, Li Jia, Dai Pan, Zhao Yong, Li Lianyan, Lu Jun, Chen Xiangfei
Opt Express. 2019 Feb 4;27(3):1941-1957. doi: 10.1364/OE.27.001941.
We propose an on-chip mode converter via two cascaded Bragg reflection processes. A forward conversion between two guided modes can be achieved with the aid of an additional mode. The proposed structure is theoretically studied and simulated via the rigorous three-dimensional finite-difference time-domain (3D-FDTD) method. The bandwidth and central wavelength of the proposed mode converter can be adjusted according to our theoretical analysis and simulation results. By applying the similar design approaches as fiber Bragg gratings, conversion spectra with different shapes can be obtained. As an example, several mode converters with bandpass and sidelobe-reduced spectra are designed. We also investigate and verify the mode conversion by experiment. Therefore, the proposed method may pave a new path for the mode converters with desired conversion spectra.
我们提出了一种通过两个级联布拉格反射过程实现的片上模式转换器。借助一个额外的模式，可以实现两种导模之间的正向转换。通过严格的三维时域有限差分（3D-FDTD）方法对所提出的结构进行了理论研究和模拟。根据我们的理论分析和模拟结果，可以调整所提出的模式转换器的带宽和中心波长。通过应用与光纤布拉格光栅类似的设计方法，可以获得不同形状的转换光谱。例如，设计了几种具有带通和旁瓣抑制光谱的模式转换器。我们还通过实验研究和验证了模式转换。因此，所提出的方法可能为具有所需转换光谱的模式转换器开辟一条新途径。
