Compensation of source wavelength changes in a closed-loop fibre optic sagnac interferometer

摘要

In a method according to the invention for compensating for variations in the wavelength of the light source of a fibre-optic gyroscope having closed control resetting circuit, use is made of the discovery that the voltage change which is necessary for a phase shift of 2 pi in a phase modulator (4) depends on the light-source wavelength. Since the voltage required for the 2 pi phase shift is regulated, the voltage value thereby provided can, according to the invention, be employed for compensating for a change in the light-source wavelength or in the scale factor, respectively. For accurate compensation, the temperature of the phase modulator (4) should also be taken into consideration.