Method for compensating a fiber optic measurement system designed to determine a mechanical quantity, comprising: providing, in the fiber optic measuring system, a first and at least a second fiber Bragg grating, which have a respective Bragg wavelength; irradiating the fiber Bragg grating with primary light; applying, to the first and second fiber Bragg grating, the mechanical quantity in such a way that the Bragg wavelengths of the fiber Bragg gratings are changed by the mechanical quantity, wherein the first and at least second fiber Bragg grating are affected essentially by an equal measure with a quantity (A) and affected by an unequal measure with the mechanical quantity (B); filtering the first and second secondary light being effected from the primary light and modified by the Bragg wavelength of the fiber Bragg grating depending on the mechanical quantity, by use of an optical filter device with a rising and a falling filter gradient, wherein the Bragg wavelength of the first fiber Bragg grating lies in a range of the rising filter gradient of the optical filter device and the Bragg wavelength of the second fiber Bragg grating lies in a range of the falling filter gradient of the optical filter device; determining the intensities of the filtered first and second secondary light; evaluating the determined intensities of the filtered first and second secondary light, wherein the evaluating of the determined intensities of the filtered first and second secondary light comprises a summation of the intensity of the first secondary light and of the intensity of the second secondary light; and determining the mechanical quantity from the intensity evaluation. providing, in the fiber optic measuring system, a first and at least a second fiber Bragg grating, which have a respective Bragg wavelength; irradiating the fiber Bragg grating with primary light; applying, to the first and second fiber Bragg grating, the mechanical quantity in such a way that the Bragg wavelengths of the fiber Bragg gratings are changed by the mechanical quantity, wherein the first and at least second fiber Bragg grating are affected essentially by an equal measure with a quantity (A) and affected by an unequal measure with the mechanical quantity (B); filtering the first and second secondary light being effected from the primary light and modified by the Bragg wavelength of the fiber Bragg grating depending on the mechanical quantity, by use of an optical filter device with a rising and a falling filter gradient, wherein the Bragg wavelength of the first fiber Bragg grating lies in a range of the rising filter gradient of the optical filter device and the Bragg wavelength of the second fiber Bragg grating lies in a range of the falling filter gradient of the optical filter device; determining the intensities of the filtered first and second secondary light; evaluating the determined intensities of the filtered first and second secondary light, wherein the evaluating of the determined intensities of the filtered first and second secondary light comprises a summation of the intensity of the first secondary light and of the intensity of the second secondary light; and determining the mechanical quantity from the intensity evaluation. <EOS>