A New Route to High Sensitivity Pressure Sensors The goal is to develop an embedded-core capillary optical fiber that exhibits highly sensitive pressure sensing capabilities. Used COMSOL Multiphysics® to study the pressure-induced displacements and mechanical stresses, calculate the effective refractive indices, and obtain the change in birefringence as a function of pressure and core location. Multiphysics Simulation 2017: Jonas Osório, Cristiano Cordeiro, Unicamp; Marcos Franco, Valdir Serrão, Instituto de Estudos Avançados, Brazil Changes in modal birefringence as a function of the position of the germanium core within the capillary wall. The case with the highest changes in birefringence due to pressure variations occurs when the core is very close to the inner radius of the fiber (top center case).