Abstract
A simple and reliable spectrum-retrieval method was proposed for the development of miniature stationary Fourier transform (FT) spectrometers based on a LiNbO₃ (LN) waveguide Mach-Zehnder interferometer (MZI) modulator. The method takes into account the wavelength dependence of the optical pathlength difference (OPD) and allows us to use a nonlinear voltage ramp to modulate the OPD. The method is based on the dispersion of the half-wave voltage, which was measured to be a monotonous polynomial function of the wavelength for the LN waveguide MZI used. With the measured dispersion of the half-wave voltage, the OPD, as a linear function of the modulating voltage, can be accurately determined at each wavelength in the near-infrared region in which the MZI used is a single-mode device. A prototype FT spectrometer was prepared using a LN waveguide MZI modulator based on the above method. The experimental results demonstrated that the spectrometer can be used for accurate determination of the laser wavelength and for liquid absorptiometry.
Published Version
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