Method for angular alignment of birefringent fibers in fiber-optic pressure/strain measurement

A simple method for angular alignment of principal birefringence axes of a highly birefringent (HB) polarization-maintaining (PM) optical fiber is presented. The method is based on longitudinal strain-induced cross-coupling phenomena which occur in HB fibers and it can be straightforwardly applied to construct a fiber-optic pressure or strain sensor independent of disturbing thermal effects. The method is also particularly suitable for splicing birefringent fiber pigtails to laser diodes in all-fiber configuration for a fiber-optic pressure (strain) sensor.