Xu Yin, Wang Jiayuan, Xiao Jinbiao, Sun Xiaohan
Laboratory of Photonics and Optical Communications, School of Electronic Science and Engineering, Southeast University, Nanjing, China.
Appl Opt. 2013 Jun 1;52(16):3737-44. doi: 10.1364/AO.52.003737.
A design scheme for silicon-based slot-waveguide crossing using a slot-to-strip mode converter (at each port) and a strip-multimode-waveguide (SMW) crossing is proposed. The guided modes of the input slot-waveguide are first efficiently transformed into that of the single-mode strip waveguide by using the mode converter, and then enter into the SMW, where fields converge at the center of the intersection due to the multimode interference effect. Consequently, the size of the input beam is much smaller than the width of the SMW at the crossing center, leading to the significant reduction of the crosstalk (CT) and radiation loss. The numerical results show that a slot-waveguide crossing operating at a wavelength of 1.55 μm with the insertion loss (IL), CT, and reflection (RT) of 0.086, -35.58, and -27.51 dB, respectively, is achieved. Moreover, the IL, CT, and RT as functions of the structural parameters together with the operating wavelength are analyzed in detail by using a finite-difference time domain method, and their fabrication tolerances are presented. In addition, the evolution of the injected fields along the propagation distance through the slot-waveguide crossing is also demonstrated.
提出了一种基于硅的槽波导交叉的设计方案，该方案在每个端口使用槽到带状模式转换器和带状多模波导（SMW）交叉。通过使用模式转换器，输入槽波导的导模首先被有效地转换为单模带状波导的导模，然后进入SMW，在那里由于多模干涉效应，场在交叉点的中心汇聚。因此，输入光束的尺寸远小于交叉中心处SMW的宽度，从而导致串扰（CT）和辐射损耗显著降低。数值结果表明，实现了一个工作在1.55μm波长的槽波导交叉，其插入损耗（IL）、CT和反射（RT）分别为0.086dB、-35.58dB和-27.51dB。此外，利用时域有限差分法详细分析了IL、CT和RT作为结构参数以及工作波长的函数，并给出了它们的制造公差。此外，还展示了注入场沿传播距离通过槽波导交叉的演变。
