In KAIST, Kumgang laser is being developed for demonstration of the kW level coherent beam combination using
stimulated Brillouin scattering phase conjugation mirrors. It will combine 4 modules of DPSSL rod amplifier which
produces 1 kW output power. It is composed of the single frequency front-end, pre-amplifier module, and main amplifier.
The output powers of the pre-amp and main amplifier module are 200 W (20 mJ @ 10 kHz / 10 ns) and 1.07kW (107 mJ
@ 10 kHz / 10 ns), respectively.
An Fourier Transform Infra-Red(FTIR) spectrometry has played an significant role in a variety of fields in recent years.
In particular, FTIR spectrometer technology has been adopted in passive remote sensing system to predict detection
probabilities of stand-off hazardous compounds. There are three steps to detect hazardous compounds. Firstly, MODerate
spectral resolution atmospheric TRANsmittance(MODTRAN) algorithm is used to calculate spectral radiances of
background and atmosphere affected by hazardous compounds. It transfers a difference of spectral radiance between
background and hazardous compounds existing region to FTIR spectroscopy system. Secondly, FTIR spectrometry
system collects an interferogram which represents spectral radiances respective to given time intervals (reciprocal of
wavenumber) and sends it to signal processing part. Lastly, the signal processing part performs Fourier Transformation
on the interferogram and identifies the spectral radiance with reference data from gas library by using Spectral Angle
Mapper(SAM) algorithm which results in visualizing the hazardous gases.
However, there are some noises which affect the interferogram and the spectrum in practice. Specifically, there are two
main noises which have critical effects on the interferogram and the spectrum by reducing its Signal to Noise Ratio(SNR)
such as detector noise, jitter of moving mirror and optics misalignment.
In this paper, a theory of the effects of the detector noise and the jitter of moving mirror on the interferogram and its
demonstration through simulation are presented.