Design And Implementation Of High Sensitivity Fiber Spectrometer Based On Area Array CCD

Spectrometer is an important instrument for spectrum detection.By measuring and analyzing the spectrum,the analysis of the composition and structure of the material is completed.Spectrometer has the advantages of fast measurement,high precision,non-destructive measurement,etc.Therefore,it has been widely used in material chemistry,petrochemical industry,optical testing,astronomy research,environmental testing,aerospace and other fields.Large size and high price almost limit the traditional spectrometer to the laboratory.In recent years,there is an urgent need for analytical instruments to move towards miniaturization and intellectualization because of the development of biomedicine and modern agriculture.The appearance of fiber spectrometers meets the demand for spectrum detection in these fields well and broadens the application scenarios of spectroscopic instruments.Other instruments based on fiber spectrometers have also been developed rapidly.The area array CCD has the advantages of high sensitivity and wide dynamic range which is suitable for fluorescence measurement,DNA sequencing,Ramanspectroscopy and low photometric detection.Therefore,it is of great practical value to develop high sensitivity fiber spectrometer based on area array CCD.According to the project design requirements and the design principle of micro-fiber spectrometer,the specific scheme is put forward in this paper.In this design,the back-thinned type area array CCD S11510-1106 of the Hamamatsu Corp is used as the detection device.The optical resolution of1 nm is obtained by using an optimized cross asymmetric Czerny-Turner optical system structure.By combining the design method of DC-DC and LDO,the complex power system of 6 voltage outputs is realized by USB power supply.The CCD drive timing design is achieved by Verilog HDL language and the signals are output by Altera's CPLD chip EPM7064 AE.After the CCD output video signal is converted by high-speed 16 bits AD chip AD9826,which has an internal correlated double sampler(CDS).Digital signals are stored in a separate static RAM,allowing data acquisition and reading to be separated.As shown by experimental results,the sensitivity of the high sensitivity spectrometer designed in this paper is11 times of that spectrometer based on linear array CCD with a dynamic range of 20000: 1 and a signal-to-noise ratio of 500: 1,which greatly improves the performance of fiber spectrometer.