片上集成光学模块具有集成小型化、低成本等优点,可在芯片尺度上实现“样品进、结果出”的即时定点检测。本文研制了一个工作波长为647 nm的荧光激发模块,集成聚合酶链式反应(PCR)生物微流控芯片和光电探测器,实现了片上荧光激发和病原体核酸检测。该荧光激发模块主要由光栅和多模干涉器两个微纳器件构成,经有限时域差分法优化,光栅激发效率可达26.3%,多模干涉器损耗低至2.8%。结合生物微流控芯片,采用等浓度梯度的Cyanine 5 (Cy5)荧光素溶液对荧光激发模块性能进行验证,光电探测器输出电压值与Cy5荧光素溶液浓度之间成线性关系,拟合曲线方差为0.9944,最低检测下限为0.0625 µmol/L。利用200 copies/μL的新型冠状病毒质粒做生物应用测试,结果表明本文所提出的荧光激发模块能满足实际PCR应用中对荧光信号激发的要求。本系统在生物荧光定量PCR、数字PCR、蛋白等实时生物荧光检测方面具有应用前景。On-chip integrated optical modules have the advantages of integrated miniaturization, low cost, etc., and can realize “sample in, result out” real-time fixed-point detection on a chip scale. In this paper, a fluorescence excitation module with an operating wavelength of 647 nm was developed to achieve on-chip fluorescence excitation and pathogen nucleic acid detection by integrating a polymerase chain reaction (PCR) bio-microfluidic chip and a photodetector. The fluorescence excitation module is mainly composed of two micro-nano devices, grating and multimode interferometer (MMI). Optimized by the Finite-difference time-domain method, the grating excitation efficiency can reach 26.3%, and the multimode interferometer loss is as low as 2.8%. The performance of the fluorescence excitation module was verified by using an equal concentration gradient of Cyanine 5 (Cy5) fluorescein solution in combination with a bio-microfluidic chip. The output voltage value of the photode
