We demonstrate experimentally a discretely tunable optical delay line (ODL) using a step-chirped subwavelength grating (SWG) waveguide Bragg grating (BG) in silicon-on-insulator (SOI). The step-chirped structure is implemented using a serial array of 10 SWG waveguide BGs. It is designed using 3D finite-difference time-domain (FDTD) and the transfer matrix method (TMM), and is fabricated using electron beam lithography with a single etch. The grating structure has a total time delay of ∼60 ps in steps of ∼6.6 ps over an operating bandwidth of 41.7 nm; the measured results are in good agreement with simulations. We demonstrate the application of the ODL for antenna beamforming in simulations; in particular, we calculate the array factors for different phased array antennas using the measured time delays.

中文翻译：

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基于步进啁啾亚波长光栅波导布拉格光栅的集成离散可调光延迟线

我们使用绝缘体上硅 (SOI) 中的步进啁啾亚波长光栅 (SWG) 波导布拉格光栅 (BG) 通过实验证明了离散可调谐光学延迟线 (ODL)。阶梯啁啾结构是使用 10 个 SWG 波导 BG 的串行阵列实现的。它使用 3D 有限差分时域 (FDTD) 和传递矩阵方法 (TMM) 设计，并使用电子束光刻和单次蚀刻制造。在 41.7 nm 的工作带宽上，光栅结构的总时间延迟约为 60 ps，步长约为 6.6 ps；测量结果与模拟非常吻合。我们在仿真中演示了 ODL 在天线波束成形中的应用；特别是，我们使用测量的时间延迟来计算不同相控阵天线的阵列系数。