Towards flexible photonic sensing skins with optical fiber sensors

We review the state-of-the-art in photonic crystal fiber (PCF) based mechanical sensing. We then introduce our recently developed highly birefringent PCF that allows pressure and force sensing when combined with a fiber Bragg grating sensor. We clarify the measurement principle and explain how the optimized microstructure of the PCF yields its record-high sensitivity. In addition we demonstrate the selectivity of our bare fiber sensor, which remains insensitive to temperature changes or axial strain. We explain how the integration of this specialty fiber sensor technology with biocompatible polymer based micro-technology provides great opportunities for flexible and stretchable photonic sensor skins. Such touch sensitive devices can therefore play an important role in the domain of biorobotic instrumentation.