Readme: Raw data from "Mid-infrared silicon-on-insulator Fourier-transform spectrometer chip", by Milos Nedeljkovic, Aitor V. Velasco, Ali Z. Khokhar, André Delâge, Pavel Cheben, and Goran Z. Mashanovich, Photonics Technology Letters (accepted 24th October 2015). This document written by Milos Nedeljkovic (m.nedeljkovic@soton.ac.uk) The raw data that was used to prepare figures 3, 4a and 4b from this manuscript is included in the Excel document "MN_ftir_PTL_2015_final_paper.xslx". The data corresponding to each of the figures is included in a separate tab: - Fig. 3: The excel table rows correspond to the measurements at different wavelength (i.e. y-axis on fig. 3), and the columns correspond to the MZI whose output is measured (i.e. x-axis on fig. 3). The value in each cell location is the calculated normalized power at each wavelength and MZI number. - Fig. 4a, and 4b: Data corresponding to spectra of a narrowband laser tuned to three different wavelengths, experimentally retrieved with a) the FTIR1 chip, b) the FTIR2 chip.