Opto-electronic circuit arrangement, especially for length measurement, and method for the operation of an interferometer

摘要

Opto-electronic circuit arrangement, especially for length measurement, having an interferometer which has a semiconductor laser whose direct current supply is overlaid by an alternating current generated by a first oscillator for altering the wavelength of the light of the laser, and which has a first photodetector which receives the light intensity in the interferometer and emits an electrical output voltage corresponding to this. The modulation of the wavelength of the light is carried out in the range between two mode change points of the laser. The alteration of the wavelength of the light is carried out continuously at a predetermined frequency in the range between two step-change points of the characteristic curve of the laser. This modulation serves in practice as a carrier on which, by changing the values of the interferometer, corresponding useful interferences are overlaid, which can later be separated out by means of phase-sensitive detectors, for which purpose a frequency-modulated reference alternating voltage is generated by means of a voltage-controlled oscillator and, in the presence of stationary interference in the interferometer, simulates identically the interference signal then modulated. By means of the quasi carrier-frequency technology, a transmission free of a d.c. voltage can be carried out, so that the electrical output signal from the interferometer can be freed from d.c. components, which are caused by a fundamental brightness of the interferometer, by means of a simple capacitor. A costly compensation to overcome these d.c. values is ... Original abstract incomplete.