Integration And Test Of Multi Channel Array Spectroscopic Detection System For Raman Temperature Measurement Lidar

Atmospheric temperature,which is the physical state parameter of the atmosphere,can characterize the degree of coldness and heat of the air,and reflects the average kinetic energy of the molecules in the air.It is an important meteorological parameter in the field of atmospheric thermodynamic process,meteorology and environment analysis.Rotational Raman temperature lidar has become a research hotspot due to its high space-time resolution and good real-time characteristics.The traditional relative temperature measurement technology needs to be calibrated by other parallel detection devices,and the accuracy of the detection depends on the calibration data.This paper aims to promote the application of Raman temperature lidar with independent measurement.A spectroscopic detection system for Raman temperature lidar is carried out by using the dependence of multiple rotational Raman spectrum lines and temperature to directly inverse the atmospheric temperature profile.It provides an effective technical approach for the fine detection of the atmospheric temperature profile.Firstly,the paper designs and simulates the Raman spectroscopic system based on the first order blazed grating as the core splitter.The theoretical diffraction position of each rotational Raman spectrum is approximately uniform(approximately 125 ?m).A spectroscopic optical path for extracting a single Raman spectral line using a uniform-linear distributed fiber array is designed,and it can effectively suppress the elastic scattering signal by cascading the secondary splitter of fiber Bragg grating(FBG).The test experiment of axial defocusing deviation is constructed.Secondly,the Raman spectroscopic system is built.The experimental system for measuring the matching performance of the fiber array to Raman spectrum,the channel coefficient and the out-of-band suppression of each channel are constructed,respectively.The deviation between the measured center wavelength and the theoretical wavelength is about 0.0029?0.0398 nm.The average wavelength difference of Raman spectrum of adjacent even rotational quantum number is approximately 0.4490 nm,the maximum deviation degree is 8.86%,the channel coefficients of each fiber channel are above 0.75,and the out-of-band suppression of Raman channels,with the rotational quantum numbers J=6,10,12,16,20,22,are 27 dB,35 dB,30.5 dB,39.3 dB,39.5 dB and 40.5 dB,respectively.Finally,a multi-channel photoelectric detection module is designed,and the static characteristic of the photoelectric integrated system are simulated using the finite element analysis method.The Raman lidar for absolute atmospheric temperature detection is integrated preliminarily,and the detection of the single channel Raman signal are completed,which verifies the feasibility of the system preliminarily.