Temperature-insensitive pressure sensor using a polarization-maintaining photonic crystal fiber based sagnac interferometer

A novel, highly sensitivity, fiber-optic pressure sensor with polarization-maintaining photonic crystal fiber (PM-PCF) based Sagnac interferometer (SI) is proposed and experimentally demonstrated. A wavelength-pressure sensitivity -3.75 nm/MPa is achieved with a 79.6-cm PM-PCF as the sensing element. Owing to the birefringence insensitivity for the PM-PCF, the sensor is inherently temperature insensitive.