Free-spectral-range(FSR)-free optical filters have always been a critical challenge for photonic integrated circuits.A high-performance FSR-free filter is highly desired for communication,spectroscopy,and sensing appl...Free-spectral-range(FSR)-free optical filters have always been a critical challenge for photonic integrated circuits.A high-performance FSR-free filter is highly desired for communication,spectroscopy,and sensing applications.Despite significant progress in integrated optical filters,the FSR-free filter with a tunable narrow-band,high out-of-band rejection,and large fabrication tolerance has rarely been demonstrated.In this paper,we propose an exact and robust design method for add-drop filters(ADFs)with an FSR-free operation capability,a sub-nanometer optical bandwidth,and a high out-of-band rejection(OBR)ratio.The achieved filter has a 3-dB bandwidth of<0.5 nm and an OBR ratio of 21.5 dB within a large waveband of 220 nm,which to the best of our knowledge,is the largest-FSR ADF demonstrated on a silicon photonic platform.The filter exhibits large tunability of 12.3 nm with a heating efficiency of 97 pm/mW and maintains the FSR-free feature in the whole tuning process.In addition,we fabri-cated a series of ADFs with different periods,which all showed reliable and excellent performances.展开更多
The microring resonator has received increas- ing attention in the optical sensing application because of its micro-size, optical property, and high sensitivity. An additional waveguide is commonly used to change the ...The microring resonator has received increas- ing attention in the optical sensing application because of its micro-size, optical property, and high sensitivity. An additional waveguide is commonly used to change the output spectra in the early research on microring resonators. In this study, we proposed a nested microring resonator that doubles the free spectral range （FSR） compared with the conventional single microring. This structure improved the sensing property as the FSR in the filter output spectra could be considered as a measurement range in the microring sensor. Moreover, the parameters including the coupling coefficient of the three coupling sections, length of the U-bend waveguide, and effective index of a waveguide were tested and carefully selected to optimize the sensing properties. The relationship between these parameters and the output spectra was demonstrated. With linear sensitivity, the structure has a good potential in sensing application.展开更多
基金National Key Research and Development Program of China(2019YFB2203003)National Natural Science Foundation of China(62175202 and 91950204)+2 种基金Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(2020R01005)the Open Research program of Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang ProvinceWestlake University(the start-up fund of Westlake University).
文摘Free-spectral-range(FSR)-free optical filters have always been a critical challenge for photonic integrated circuits.A high-performance FSR-free filter is highly desired for communication,spectroscopy,and sensing applications.Despite significant progress in integrated optical filters,the FSR-free filter with a tunable narrow-band,high out-of-band rejection,and large fabrication tolerance has rarely been demonstrated.In this paper,we propose an exact and robust design method for add-drop filters(ADFs)with an FSR-free operation capability,a sub-nanometer optical bandwidth,and a high out-of-band rejection(OBR)ratio.The achieved filter has a 3-dB bandwidth of<0.5 nm and an OBR ratio of 21.5 dB within a large waveband of 220 nm,which to the best of our knowledge,is the largest-FSR ADF demonstrated on a silicon photonic platform.The filter exhibits large tunability of 12.3 nm with a heating efficiency of 97 pm/mW and maintains the FSR-free feature in the whole tuning process.In addition,we fabri-cated a series of ADFs with different periods,which all showed reliable and excellent performances.
基金This study was supported by the National Natural Science Foundation of China （Grant Nos. 61601253 and 6150127 1） and K. C. Wong Magna Fund in Ningbo University.
文摘The microring resonator has received increas- ing attention in the optical sensing application because of its micro-size, optical property, and high sensitivity. An additional waveguide is commonly used to change the output spectra in the early research on microring resonators. In this study, we proposed a nested microring resonator that doubles the free spectral range （FSR） compared with the conventional single microring. This structure improved the sensing property as the FSR in the filter output spectra could be considered as a measurement range in the microring sensor. Moreover, the parameters including the coupling coefficient of the three coupling sections, length of the U-bend waveguide, and effective index of a waveguide were tested and carefully selected to optimize the sensing properties. The relationship between these parameters and the output spectra was demonstrated. With linear sensitivity, the structure has a good potential in sensing application.
