Temperature Compensated Strain Sensor Based on Cascaded Sagnac Interferometers and All-Solid Birefringent Hybrid Photonic Crystal Fibers

We demonstrate a temperature compensated strain sensor with two cascaded Sagnac interferometers, that provide strain sensing and temperature compensation, respectively. The Sagnac interferometers use an all-solid hybrid photonic crystal fiber with stress-induced birefringence. The stress-induced birefringent fiber is known to offer the maximum strain sensitivity, but also to suffer from temperature crosstalk. Our experimental results show that the cascaded Sagnac sensor can suppress the crosstalk to a temperature upto 0.33 με/ºC, while still providing a high strain sensitivity of ~25.6 pm}/με.