Spectral noise due to measurement errors of Mach-Zehnder interferometer optical path phases in a complex Fourier-transform integrated-optic spatial heterodyne spectrometer

We calculate the root-mean-square (rms) value of the spectral noise caused by optical path phase measurement errors in a spatial heterodyne spectrometer (SHS) featuring a complex Fourier transformation. We show that the rms value is proportional to the rms error of the phase measurement and the proportionality coefficient is given analytically. The relationship enables us to estimate the possible performance of the SHS such as the sidelobe suppression ratio for a given measurement error.