Research On Monolithic Integration Of Array Waveguide Grating And PIN Photo-detectors For Fluorescence Detection

Instruments,which can realize real-time,fast and simple detection,are more and more needed in industries and daily life.Among these tools,the fluorescence spectrometer is used in many applications with the meries of high precision,anti-interference and non-invasive,etc.However,most of the fluorescence spectrometers are bulky and expensive,can only used in the laboratory.Therefore,miniature fluorescence spectrometers have been in demand for portable or in field detections.Researchers have developed many miniaturization approaches of fluorescence spectrometer,among which the dispersion module and photodetector array integrated into a single chip is a low-cost and very effective scheme.As a popular wavelength division-multiplexing device,arrayed waveguide grating(AWG)is one of the most attractive solution of miniaturization of dispersive spectrometer because of its flexible design,low cost and simple process.However,how to integrate the AWG and photodetector array into a single chip with less insert loss was still a difficult issue.An AWG was monolithic integrated with a PIN photodetector array in the dissertation for the application of polychromatic fluorescent labeling detection.The design,fabrication and characteriazation of the chip were discussed.The main contents of this paper are as follows:1.A new coupling approach of waveguide and PIN photodetectors were designed and fabricated.The output optical signals was allowed into the I region of the PIN diode directly without passing the P or N region or the surface of the device to reduce the insert loss.In the test,the dark current of the PIN photodetector is 0.21 nA,and the responsivity is 0.84 A/W at the 650 nm optical inputs.2.The layout of the six-channel-out AWG was designed and optimized using the OptiBPM software to keep the insert loss in the range of 4.83 to 6.82 dB in the simulation.3.The process parameters of monolithic integration of arrayed waveguide grating and PIN photodetector was optimized,and finally the fluorescent detection chip was realized.4.The chip was connected with a weak photocurrent detection IC chip designed by our research group to form a fluorescence detection module.A series of test was presented to verify the performance of the chip using a broadband light source,a 650 nm wavelength laser and two kind of fluorescent quantum dot dye with central wavelength at 700 nm and 785 nm,respectively.The test results are demonstrated to be basically consistent with the simulation.The innovation of this dissertation includes the new coupling design of waveguide and PIN photodetector;the realization of the monolithic integrated AWG and PIN photodetectors and the verification of its performance in polychromatic fluorescent labeling detection.