[Study on miniature static Fourier transform spectrometer used in laser warning receiver].
A miniature static Fourier transform spectrometer (MSFTS) as the component of coherent discriminating laser warning receiver (CDLWR) was designed in the present study by using a modified wedge interfering etalon (MWIE), a linear charge couple device (CCD) and a fast digital signal processor (DSP). The MSFTS possesses some advantages such as small volume, low cost, high speed, stable performance and good signal to noise ratio. MSFTS can detect the spectrum of HIPL, the short pulse width of laser is about 10 ns, and the spectrum scope is from 400 to 1 100 nm. The key element of MSFTS is MWIE which is composed of two triangle prisms, one of which is a right angle prism with two equal acute angles of 45 degrees, another prism has no right angle, one of the acute angles is 45 degrees, and another is slightly smaller than 45 degrees. The long sides of the two prisms were bonded by transparent glass glue, and the adhesive surface is plated with special material which serves as a beam splitter (BS). The incident laser will be split into two equal strength beams with continuously changing optical path difference, the two beams will interfere and form interferogram which will be focused by a cylinder as a line and transformed as s electronic signal by CCD. The electronic signal was processed by using a DSP, and finally we obtained the spectrum of the incident hostile laser by applying fast Fourier transform (FFT). We have established the experiment system of MSFTS, and used the system and the spectrometer Q8344A made by Advantest Company in Japan to measure the spectra of the seven lasers with different central wavelengths: 635, 650, 670, 780, 808, 850 and 980 nm. The measurement result shows that the worst wavelength resolution is 8. 845 nm at 1 100 nm, the best wavelength resolution is 1.170 nm at 400 nm, the relative average error of central wavelength is 0.269 nm, the absolute average error is 0.919 nm and signal-to-noise ratio of our experiment system is better than that of Q8344A.
Tian
Er-Ming
EM
National Key Laboratory for Electronic Measurement Technology and Instrument, Taiyuan 030051, China. tem_123@163.com
Zhang
Ji-Long
JL
Li
Xiao
X
Zhang
Yue
Y
Wang
Zhi-Bin
ZB