An optical measurement device comprising: a light source configured to generate an emitted light beam; a first beam splitter configured to divide the emitted light beam into a compensation light beam and a measurement light beam; a second beam splitter configured to transmit the compensation light beam from the first beam splitter; a first photodetector configured to detect the compensation light beam transmitted by the second beam splitter ; and a second photodetector configured to detect the measurement light beam reflected from the first beam splitter , wherein wavelength dependent transmittance and wavelength dependent reflectance characteristics of the first beam splitter and the second beam splitter are configured to be identical, wherein the compensation light is a part of the emitted light reflected by the first beam splitter , the measurement light is a part of the emitted light transmitted through the first beam splitter , the compensation light beam is transmitted through the second beam splitter to the first photodetector , and the measurement light beam is reflected by a reference mirror or an analyte and then reflected by the first beam splitter to the second photodetector , wherein the number of transmissions by the first beam splitter and the second beam splitter in a first optical path that couples the light source and the first photodetector is equal to the number of transmissions by the first beam splitter in a second optical path that couples the light source and the second photodetector , and the number of reflections by the first beam splitter and the second beam splitter in the first optical path is equal to the number of reflections by the first beam splitter in the second optical path. a light source configured to generate an emitted light beam; a first beam splitter configured to divide the emitted light beam into a compensation light beam and a measurement light beam; a second beam splitter configured to transmit the compensation light beam from the first beam splitter; a first photodetector configured to detect the compensation light beam transmitted by the second beam splitter ; and a second photodetector configured to detect the measurement light beam reflected from the first beam splitter , wherein wavelength dependent transmittance and wavelength dependent reflectance characteristics of the first beam splitter and the second beam splitter are configured to be identical, wherein the compensation light is a part of the emitted light reflected by the first beam splitter , the measurement light is a part of the emitted light transmitted through the first beam splitter , the compensation light beam is transmitted through the second beam splitter to the first photodetector , and the measurement light beam is reflected by a reference mirror or an analyte and then reflected by the first beam splitter to the second photodetector , wherein the number of transmissions by the first beam splitter and the second beam splitter in a first optical path that couples the light source and the first photodetector is equal to the number of transmissions by the first beam splitter in a second optical path that couples the light source and the second photodetector , and the number of reflections by the first beam splitter and the second beam splitter in the first optical path is equal to the number of reflections by the first beam splitter in the second optical path. <EOS>