Double-Side Notched Long-Period Fiber Gratings fabricated by Using an Inductively Coupled Plasma for Force Sensing

This study used an inductively coupled plasma (ICP) dry etching process with a metal amplitude mask to fabricate a double-side notched long-period fiber grating (DNLPFG) for loading sensing. The DNLPFG exhibited increasing resonance attenuation loss for a particular wavelength when subjected to loading. When the DNLPFG was subjected to force loading, the transmission spectra were changed, showing a with wavelength shift and resonance attenuation loss. The experimental results showed that the resonant dip of the DNLPFG increased with increasing loading. The maximum resonant dip of the 40-μm DNLPFG sensor was −26.522 dB under 0.049-N loading, and the largest force sensitivity was −436.664 dB/N. The results demonstrate that the proposed DNLPFG has potential for force sensing applications.