Opt Lett. 2019 Mar 15;44(6):1411-1414. doi: 10.1364/OL.44.001411.
We propose and experimentally demonstrate a microwave photonic (MWP) notch filter based on a silica microsphere cavity. By using a high-Q-factor (∼1e7) cavity with a diameter of 132 um, the filter bandwidth can be easily decreased to 15 MHz in terms of simple fabrication and flexible coupling. Then we use the advanced modulation technique based on a dual parallel Mach-Zehnder modulator to further improve peak rejection (PR). The experimental results show that the MWP notch filter with its PR beyond 55 dB and frequency tunability range over 8 GHz has been achieved in combination with double-sideband modulation. To the best of our knowledge, this is a record for PR and bandwidth considered simultaneously for an MWP filter based on silica microcavities. Thus, the proposed MWP filter will be useful in the fields of microwave photonic signal processing, radar systems, etc.
我们提出并实验演示了一种基于二氧化硅微球腔的微波光子（MWP）陷波滤波器。通过使用具有 132 µm 直径的高 Q 因子（约 1e7）腔，仅通过简单的制造和灵活的耦合，滤波器带宽可轻松降低至 15 MHz。然后，我们使用基于双平行马赫-曾德尔调制器的先进调制技术进一步提高峰值抑制比（PR）。实验结果表明，通过双边带调制，MWP 陷波滤波器的 PR 超过 55 dB，频率可调谐范围超过 8 GHz，这是基于二氧化硅微腔的 MWP 滤波器在 PR 和带宽方面的记录。因此，所提出的 MWP 滤波器将在微波光子信号处理、雷达系统等领域有用。
