Phase OFDR-based absolute temperature/stress measurement method

The invention discloses an absolute temperature and stress measurement method based on a phase OFDR, and relates to the field of distributed optical fiber sensing. Performing beam splitting on the continuous wave laser output by the tuning laser to obtain a first light beam and a second light beam; the first light beam outputs a clock signal or a wavelength correction signal in the system through the auxiliary interferometer; the second light beam outputs a double-path OFDR time domain signal through the main interferometer; the main interferometer is an OFDR (Optical Frequency Domain Reflectometer) detection unit comprising a double-path symmetrical structure; differential operation is carried out on the OFDR time domain signals corresponding to the front weak reflection point and the rear weak reflection point on the sensing optical fiber to obtain a fast-axis optical phase and a slow-axis optical phase; performing differential operation on the fast-axis optical phase and the slow-axis optical phase to obta