Functional materials infiltrated photonic crystal fibers are optical devices that are wavelength tunable

all in fiber structure and easy to be integrated into optical systems

and have been a prominent research focus in optical fiber photonic devices.A highly sensitive strain sensor is made by selectively infiltrating high refractive index matching liquid into the air holes adjacent to the fiber core of a hollow core photonic crystal fiber (PCF) by capillary force

and splicing single mode fibers at both ends of the PCF.A strain sensitivity of 4.36pm/ is obtained by a device with infiltration length of 30mm and liquid refractive index of 1.508.The experimental results agree well with the simulation predictions.Such a device can be used for strain sensing with high sensitivity.