Fiber optic pressure sensors

The authors focus on measuring static pressure with both a fiber-optic Mach-Zehnder interferometer and a single-mode fiber. They investigate the effect of such a pressure on a single-mode optical fiber. It is shown that, as predicted, anisotropic stress causes a birefringence in the fiber which in turn causes a change in the state of polarization (SOP) of the transmitted light. Since this phenomenon has a directional asymmetry, it was sensitive to the input SOP of the light. The interferometer was used to show that the isotropic and lateral components of the anisotropic static pressure were separable. A conventional single-mode fiber will suffice to detect the asymmetry in the sensed pressure