A 3-D-printed, temperature sensor based on mechanically-induced long period fibre gratings

We demonstrate the implementation of a temperature sensor based on mechanically induced long-period fibre gratings (MILPFGs) using a 3-D printing technology. Our sensor has an assembled structure with a periodically V-grooved plate, a flat cradle, and an assembly case, all of which are 3-D-printed with a thermoplastic of acrylonitrile butadiene styrene (ABS). Our sensor exhibits the linear change of both wavelength and loss of the resonance peak depending on environmental temperature, unlike the conventional LPFGs-based temperature sensors. The observed resonance loss change can be attributed to the micro-expansion of our 3-D-printed assembly structure, which decreases the screw-induced strain. The temperature sensitivities of our sensor are measured to be −97 pm/°C and 0.33 dB/°C for the wavelength and loss of the resonance peak, respectively.