Strain and temperature discrimination based on a Sagnac interferometer with three sections of high birefringence fibers

We present an all-fiber sensor for strain and temperature discrimination by inserting three sections of high birefringence fibers into a Sagnac loop. The principle for strain and temperature discrimination is based on monitoring the wavelength shifts of two different resonant dips that show different sensitivities to temperature and strain. The sensitivities for strain and temperature are measured to be $-{0.93}\;{\rm nm}/^\circ {\rm C}$−0.93nm/∘C and 21 pm/µɛ with discriminative errors of $\pm {0.3}^\circ {\rm C}$±0.3∘C and $\pm {12}\;\unicode{x00B5}\varepsilon$±12µe. The proposed sensor with high sensitivity, simple configuration, and low cost may be a promising candidate for various strain and temperature-sensing applications.