Simultaneous hydrostatic pressure and temperature measurement employing a LP01-LP11 fiber-optic polarization-sensitive intermodal interferometer

The authors propose a polarization-sensitive LP₀₁-LP ₁₁ two-mode interferometer employing a highly birefringent fiber for the direct simultaneous measurement of high hydrostatic pressure and ambient temperature. The results show that the most suitable type of birefringent fiber for this type of two-parameter sensing is the bow-tie fiber, whereas elliptical-core and D-shaped fibers exhibit nonlinear dependence of their sensitivities. The results are found to be in agreement with a recently developed Müller-Stokes formalism describing polarization effects in the case of two-mode interference. Initial calibration of the two parameter simultaneous pressure-and-temperature sensor has also been performed up to 100 MPa using a primary pressure standard