All-fiber vibration sensor based on nano-wire grid polarizer

摘要

We propose a novel all-fiber vibration sensor without any bulk optical element by employing an in-line nano-wire grid (NWG) fiber polarizer. The NWG is directly fabricated on tip of a single mode fiber (SMF) by focused ion beam technology. According to effective medium theory, the sub-wavelength NWG has strong polarization properties. In our experiment, the reflection contrast between transverse electric and transverse magnetic modes reaches 14 dB, which is sensitive enough to monitor polarization change induced by photoelastic effect. We apply a sinusoidal vibration signal generated by a piezoelectric transducer onto the fiber. The output light signal from the SMF coincides well with the vibration source. The frequency response of the sensor is measured from 20 Hz to 4 kHz showing great consistency.