Pilot demonstration of refractive index sensing using polymer optical fiber crushed with slotted screwdriver

We demonstrate power-based refractive index (RI) sensing using a polymer optical fiber (POF) crushed with a slotted screwdriver. This structure can be easily fabricated by simply pressing the end of a slotted screwdriver against part of the POF. Neither external heat sources, chemicals, nor ultrasonic transducers, which have been conventionally used, are necessary. The transmitted power has a linear RI dependence in the RI range from ~1.32 to ~1.43 (coefficient: 173 dB/RIU (RI unit)). The temperature dependence of the transmitted power is experimentally shown to be negligible, which indicates the potential of this structure as a temperature-independent RI sensor.