In this project, a Fourier transform spectrometer (FTS) was developed to characterize the emission spectra of four different superluminescent diodes (SLDs): red, green, blue, and white. The spectrometer was based on a Michelson interferometer, enabling precise spectral analysis through interference-based measurements. To achieve accurate calibration of the optical path difference (OPD), a He-Ne laser was used as a reference to provide an equidistant sampling grid required for Fourier transformation. The moving mirror was translated at a constant velocity, and interferograms were recorded during the linear region where the signal remained stable. For each measurement, approximately 20,000 raw data points were collected per channel, and these were resampled based on the zero crossings of the He-Ne laser signal. Subsequently, Fourier transformation was applied to the resampled data to obtain the corresponding spectra. The resulting spectra successfully revealed the broadband emission characteristics of the SLDs.
This study demonstrates that meaningful spectral information can be extracted using only a laser, a broadband source, and a few optical components, provided that appropriate signal processing techniques are applied. The results highlight the significance of the Fourier transform spectrometer design, which enables high-resolution spectral analysis through interferometric measurements.