An optical Fourier Transform spectrometer based on the Michelson interferometer with angle difference between two mirrors

An optical spectrometer based on the Fourier transform is presented. Both the measured light and reference light are illuminated into a Michelson interferometer with angle difference between two mirrors, and the Fourier transform spectra of the interference fringes are obtained by using charge-coupled device (CCD) and the field-programmable gate array (FPGA). The peak point in the Fourier transform spectra of the reference light is used to calibrate the measured light, and the wavelength of the measured light can be detected by calculating the Fourier transform spectra between the measured light and the reference light. Due to the Michelson interferometer with angle difference between two mirrors, the Fourier transform spectrometer is realized without any mechanical movement, and the accuracy of the optical spectrometer is improved by propagating two lights into the common optical path in the same Michelson interferometer. The experiment shows that the maximum error is 1.15 nm. The proposed method possesses high performance, high reliability, and low cost.