General Waveguide Bend Design Based on Cubic Spline Interpolation and Inverse Design

• DOI: 10.1109/jlt.2024.3370675
• Publication Date: 2024-02-27T19:20:27Z
• Authors: Enge Zhang; Shanglin Yang; Lei Zhang
• Keywords: Spline (mechanical); Monotone cubic interpolation; Interpolation; Waveguide

Silicon waveguide bends are key components that affect the packing density and scalability of photonic integrated circuits. Traditional bend design methods rely on well-established functions such as Euler spirals or Bezier curves, which have limited parameter spaces, limiting discovery compact with higher performance. Here, we propose a general approach to design. For given radius, our method uses cubic spline interpolation an inverse algorithm obtain optimal geometry support number modes. We refine particle swarm optimization reduce need for tuning increase its ability avoid local optima. As result these modifications, process becomes less complicated more efficient. To demonstrate effectiveness proposed method, fabricate three supporting one, two, modes radii 2.5 μm, 4 5 respectively. The measured (simulated) insertion losses than 0.012 (0.009) dB, 0.04 (0.028) dB 0.059 (0.048) per 90°, crosstalk between latter two is –23.6 (–36.1) –19.7 (–26.5) provides effective tool designing multimode future