C-OTDR	coherent optical time domain reflectometry
DVS	distributed vibration sensing
DAS	distributed acoustic sensing
DTS	distributed temperature sensing
DTGS	distributed temperature gradient sensing
FBG	fiber Bragg grating
OFDR	optical frequency domain reflectometry
SMF	single mode fiber
FFT	fast Fourier transform
STFT	short time Fourier transform
PSD	power spectral density
ULL	ultra low loss
FUT	fiber under test