JPH0440649B

PURPOSE:To measure temp. change as interference output change, by using the rectangularly crossing 2 transmission paths of an optical fiber retaining a polarized face as the 2 light paths of an interferometer, and utilizing change of the difference between the lengths of 2 paths dependent on temp. CONSTITUTION:Light waves emitted from a light source 51 are converted into a linearly polarized light with a polarizing plate 52. These linearly polarized waves are inclined with a half wavelength plate 53 at the middle of 2 axes of an optical fiber 54 capable of retaining a polarized face, crossing each other at right angles placed in a temp. measurement object 58. At the side of the output, a light receiver 56 receives only the components of the rectangularly crossing 2 light waves in the axial directions of a light detector 55 through this detector 55. This output can be monitored continuously, for example, by a recorder 57 or the like. Temp. change can be thus measured.