F-P cascade optical fiber sensor for measuring seawater temperature and salinity

The utility model discloses an F-P cascade optical fiber sensor for measuring seawater temperature and salinity, which is composed of an F-P cascade optical fiber sensing structure for measuring seawater temperature and salinity and a demodulator, the optical fiber sensing structure and the demodulator are connected through a single-mode optical fiber, and the optical fiber sensing structure is formed by cascading a temperature sensing cavity and a salinity sensing cavity; the temperature sensing cavity and the salinity sensing cavity are isolated by the temperature-sensitive material film; according to the sensing structure designed by the utility model, the capillary quartz tube and the temperature-sensitive material are combined, so that the temperature measurement sensitivity is greatly improved; meanwhile, based on the principle of temperature compensation, correction of salinity measurement is realized by utilizing an F-P cascade structure, and the salinity measurement precision is improved; the device