标题： 具有螺旋光栅的集成任意滤波器：设计与表征 显示英文标题

标题： Integrated Arbitrary Filter with Spiral Gratings: Design and Characterization

摘要： 我们报告了一种高性能集成任意滤波器的设计和表征，该滤波器的工作波长范围从1450纳米到1640纳米。 滤波器的目标光谱被选择用来抑制夜空中的OH发射线，这对地基天文望远镜来说至关重要。 这种类型的滤波器以其宽广的光谱范围、高抑制比和窄陷波宽度为特点。 传统上，只有光纤布拉格光栅才能成功实现这一目标。 我们在此展示的技术被证明对于芯片平台非常有效，这可以为设备的尺寸、性能和成本带来许多好处。 在设计部分，比较了两种逆散射算法，即频域离散层剥离(f-DLP)和时域离散层剥离(t-DLP)。 发现f-DLP在光栅重构方面具有更高的准确性和鲁棒性。 提出了一种方法来解决DLP算法中由于非零层大小引起的非均匀性问题。 设计的55个陷波滤波器长度为50毫米，并在一个总长度为63毫米的紧凑型Si3N4/SiO2螺旋波导上实现。 实验表明，该器件的插入损耗低至2.5分贝，波导传播损耗低至0.10分贝/厘米。 我们还能够实现均匀的陷波深度和约28分贝和0.22纳米的3分贝带宽。 显示英文摘要

摘要： We report the design and characterization of a high performance integrated arbitrary filter from 1450 nm to 1640 nm. The filter's target spectrum is chosen to suppress the night-sky OH emission lines, which is critical for ground-based astronomical telescopes. This type of filter is featured by its large spectral range, high rejection ratio and narrow notch width. Traditionally it is only successfully accomplished with fiber Bragg gratings. The technique we demonstrate here is proven to be very efficient for on-chip platforms, which can bring many benefits for device footprint, performance and cost. For the design part, two inverse scattering algorithms are compared, the frequency domain discrete layer-peeling (f-DLP) and the time domain discrete layer-peeling (t-DLP). f-DLP is found to be superior for the grating reconstruction in terms of accuracy and robustness. A method is proposed to resolve the non-uniformity issue caused by the non-zero layer size in the DLP algorithm. The designed 55-notch filter is 50-mm-long and implemented on a compact Si3N4/SiO2 spiral waveguide with a total length of 63 mm. Experimentally, we demonstrate that the device has a insertion loss as low as 2.5 dB, and that the waveguide propagation loss is as low as 0.10 dB/cm. We are also able to achieve uniform notch depths and 3-dB widths of about 28 dB and 0.22 nm, respectively.