Fig. 1. Principle of Brillouin spectrometer

Fig. 2. Spectra measurement procedure of Brillouin spectrometer. (a) Signal under test (SUT); (b) pump signal; (c) output signal amplified by stimulated Brillouin scattering; (d) split spectra after baseline removing; (e) full band split spectra by tunable laser; (f) measured spectra obtained by spectrum reconstruction algorithm

Fig. 3. Optical path and wavelength transmission property of FP etalon. (a) Optical path; (b) wavelength transmission property

Fig. 4. Characteristic spectrum of HCN+¹²CO+¹³CO mixed gas

Fig. 5. Ghost lines generation mechanism in Brillouin spectrometer. (a) Gain property of stimulated Brillouin scattering; (b) measured data with ghost

Fig. 6. Ghost lines identification and correction procedure. (a) Peak fitting; (b) valley fitting; (c) spectra after ghost lines correction

Fig. 7. Calibration of relative wavelength. (a) Experimental setup; (b) measured data; (c) fitting result of wavelength calibration; (d) residual of calibration wavelength

Fig. 8. Calibration of absolute wavelength. (a) Experimental setup; (b) measured data; (c) fitting result of wavelength calibration; (d) residual of calibration wavelength

Fig. 9. Measured spectra. (a) Optical fiber filter; (b) single side-band modulation signal