In silicon photonic waveguides, the on-chip integration of high-performance nanomaterials is considerably important to enable the waveguide sensing function. Herein, the in situ self-assembly of the low refractive index (RI) metal–organic framework nanomaterial ZIF-8 with a large surface area and high porosity on the surface of a designated SiO₂ waveguide for evanescent wave sensing is demonstrated. The surface morphology and transmission loss of the nano-functionalized waveguide are investigated. The specific design and fabrication of asymmetric Mach–Zehnder interferometers (AMZIs) are performed based on the optical properties of ZIF-8. Such efforts in waveguide engineering result in an output interfering spectrum of nano-functionalized AMZI with an ultra-high extinction ratio (28.6 dB), low insertion loss (∼13 dB) and suitable free spectral range (∼30 nm). More significantly, the outstanding sensing features of ZIF-8 are successfully realized on the SiO₂ waveguide chip. The results of ethanol detection show that the AMZI sensor has a large detection range (0 to 1000 ppm), high sensitivity (19 pm ppm⁻¹ from 0 to 50 ppm or 41 pm ppm⁻¹ from 600 to 1000 ppm) and low detection limit (1.6 ppm or 740 ppb). This combination of nanotechnology and optical waveguide technology is promising to push forward lab-on-waveguide technology for volatile organic compound (VOC) detection.

中文翻译：

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用于敏感 VOC 传感的 SiO2 波导上的金属有机骨架纳米材料的片上集成

在硅光子波导中，高性能纳米材料的片上集成对于实现波导传感功能非常重要。在此，具有大表面积和高孔隙率的低折射率 (RI) 金属-有机骨架纳米材料 ZIF-8 在指定 SiO ₂表面的原位自组装演示了用于倏逝波传感的波导。研究了纳米功能化波导的表面形貌和传输损耗。非对称马赫-曾德干涉仪 (AMZI) 的具体设计和制造是基于 ZIF-8 的光学特性进行的。波导工程中的这些努力导致纳米功能化 AMZI 的输出干扰光谱具有超高消光比 (28.6 dB)、低插入损耗 (~13 dB) 和合适的自由光谱范围 (~30 nm)。更重要的是，ZIF-8 出色的传感特性在 SiO ₂波导芯片上成功实现。乙醇检测结果表明，AMZI传感器检测范围大（0~1000 ppm），灵敏度高（19 pm ppm ^-1从 0 到 50 ppm 或 41 pm ppm ^-1从 600 到 1000 ppm）和低检测限（1.6 ppm 或 740 ppb）。这种纳米技术和光波导技术的结合有望推动用于挥发性有机化合物 (VOC) 检测的波导实验室技术。