Abstract: An optoelectronic apparatus for the remote measuring of a physical magnitude which comprises two light sources emitting luminous fluxes centered on two different wavelengths and means for controlling the alternate operation of these light sources. A sensor is provided for receiving the luminous flux emitted by the respective light sources and causing a periodic spectral modulation of the luminous flux a frequency depending on the value of the physical magnitude to be measured. An analysis means is provided for analyzing the luminous flux transmitted by the sensor, the analysis means being of the static type and including a birefringent element which is tuned to the sensor and produces an optical path difference close to that produced by the sensor.