Highly stable 3D printed microsensors at optical fiber tips

The ability of a sensor to provide stable and reliable response while operating in harsh environments is crucial for many applications. It is highly dependent on the composition of the material constituting the sensor. In this work, we investigated the 3D printing of three types of materials to evaluate their performance for temperature and pressure sensing. To this end, Fabry-Perrot (FP) optical microsensors were fabricated on optical fiber tip using two-photon polymerization 3D printing. First, we investigated organic and hybrid polymers as sensing materials using commercial resins. The obtained FP microcavities showed good optical characteristics around a temperature of 80 °C for IP-S® and 180 °C for OrmoComp®. Spectral shifts and hysteresis were observed over time, making them unsuitable for using as reliable sensors even at lower temperatures. To overcome this problem, homemade silica-based hybrid resin was used to fabricate FP optical sensors on fiber tips. After debinding and sintering at a temperature up to 1200 °C, inorganic silica-based fiber optic sensors were obtained. Temperature sensing has been recorded in the range of 20 °C to 1000 °C using these silica-based FPs. No hysteresis was recorded in the range 20–800 °C in accordance with the accuracy of our experiment. Furthermore, we evaluated the same type of silica-based FP cavity for pressure sensing in the range of 1–138 bars. The sensor showed a linear response to pressure changes in this range. The obtained results demonstrate that our compact silica-based sensors are promising candidates for temperature and pressure sensing in a harsh environment with very good aging and stability. • Fabry-Perot sensors were 3D printed on fiber tip by two-photon polymerization. • Polymer Fabry-Perot sensors showed unstability around 80 °C. • Silica-based Fabry-Perot sensors have been sintered at 1100 °C. • Reflected comb exhibits stable visibility of 0.87 up to 1000 °C. • High stability of optical glass sensors was observed up to 800 °C and 138 bars.