Device and method for measuring FP polarization characteristic by using laser light source in whispering gallery mode

The invention discloses a device and a method for measuring an FP polarization characteristic by using a laser light source in a whispering gallery mode. The device comprises a seed laser, a first polarizing plate, a second polarizing plate, a spectroscope, a beam contracting system, a lens and a PDMS which are sequentially arranged; the spectroscope is correspondingly provided with an energy meter; the PDMS is correspondingly provided with a first spectrograph; one end of the PDMS is pre-arranged in a first optical fiber, and the other end of the PDMS is pre-arranged in a second optical fiber; laser light passing through the lens is focused to the end surface of the first optical fiber; the second optical fiber is correspondingly provided with a collimator; the collimator is correspondingly provided with a first beam splitter; the first beam splitter is correspondingly provided with a second beam splitter and a diaphragm; the second beam splitter is correspondingly provided with a second spectrometer and a f