Abstract: The device (2) for calibrating a fiber optic sensor in a bearing device (1), comprises an optical fiber (3) including a set (6) of refraction gratings configured to identify the optical fiber (3), the device comprising: an optical interrogator (7) configured to emit an optical signal into the optical fiber (3), collecting means (9) for collecting the reflected wavelength of each refraction grating illuminated by the optical signal, first processing means (10) to process the collected reflected wavelengths of the set (6) of refraction gratings to identify the optical fiber (3), and second processing means (11) to associate the identified optical fiber (3) with a calibration data table of the said fiber optic sensor.