"基于绝缘体上硅的高性能片上光学平顶滤波器设计及性能分析"

Abstract The document introduces a low-ripple factor, high shape factor on-chip optical flat-top filter scheme based on silicon on an insulator. The scheme utilizes a racetrack-ring resonator-assisted asymmetric Mach-Zehnder interferometer structure, which can achieve a ripple factor (the ratio of maximum power to minimum power in the passband) of approximately 0.11 dB, a shape factor (the ratio of the 3 dB bandwidth to the 20 dB bandwidth) of about 0.79, a sidelobe suppression ratio of approximately 22.78 dB, an insertion loss of about 0.22 dB, and a free spectral range (FSR) of around 5.22 nm in the filtering spectrum. By proportionally reducing the relevant dimensions without changing the structure, the FSR of the filtering curve can be correspondingly increased. When the size is reduced to 58% of the original, the FSR increases to 11.17 nm, the shape factor becomes 0.81, the insertion loss is 0.21 dB, and the ripple factor and sidelobe suppression ratio are approximately 0.14 dB and 16.83 dB, respectively. Furthermore, the document simulates the effect of process errors in the actual production of small-sized filters on the device's filtering performance and further proposes and demonstrates the conclusion that the use of on-chip microthermal electrodes for heating the device can effectively mitigate this impact. This flat-top filter has the advantages of small size, low weight, simple manufacturing, large process tolerance, low ripple factor, high shape factor, and low loss. It can be widely used in optical signal processing fields such as frequency comb generation and optical switches.