High sensitivity temperature sensor based on Fresnel reflection with thermosensitive polymer: control of morphology and coating thickness

Abstract

We propose and experimentally demonstrate a simple fabrication and high sensitivity Fabry-Perot interferometer polymer (FPIP)-coated temperature sensor based on Fresnel reflection. The single mode fiber end-face was coated with a polycarbonate (PC) or poly(methyl methacrylate) (PMMA) thermosensitive polymer. The experimental results indicate that the FPIP sensor coated with PMMA exhibits the average temperature sensitivities of 312.5 and 257.0 pm °C−1 for the thicknesses of 5.2 and 6.5 μm, respectively, in the temperature range of 26 °C-80 °C. Meanwhile, the FPIP sensor coated with PC exhibits the average temperature sensitivities of 245.4 and 103.6 pm °C−1 for the thicknesses of 4.9 and 9.9 μm, respectively, in the temperature range of 26 °C-140 °C. The FPIP sensor coated with PC indicates a relatively low sensitivity compared to PMMA coated sensor. However, the available operating temperature range for PC sensor is larger than PMMA.

Simply Fabricated Inexpensive Dual-Polymer-Coated Fabry-Perot Interferometer-Based Temperature Sensors with High Sensitivity

“…As a result, the fabricated sensors were ready for temperature measurement tests. Sensors with non-uniform, rough coatings with air bubbles have compromised reflection spectra [35]. The reflected interference pattern of the reference SMF corresponds to a straight line (Figure 3a), which indicates that most of the light was communicated through the end phase of the SMF.…”

“…The DFPIbased sensor utilizes the principle of Fresnel reflection. Fresnel's reflection is an optical phenomenon occurring at the interface between two media with different refractive indices [34][35][36]. As illustrated in Scheme 1, the DFPI-based sensor has a total of three reflection surfaces on the tip, corresponding to the interface between the fiber and the first polymer, the interface between the first and second polymers, and the interface between the second polymer and air; these correspond, respectively, to the Fresnel reflection coefficients R 1 , R 2 , and R 3 .…”

Enhancing Temperature Sensitivity of the Fabry–Perot Interferometer Sensor with Optimization of the Coating Thickness of Polystyrene

“…Moreover, PS exhibited much higher TOC than those of PVC, PC, NOA 61, NOA 65, and epoxy. To date, PMMA is the most widely utilized polymer for the application to the temperature sensor due to its high sensitivity and good adhesive characteristics [28]. However, it cannot be applicable for long temperature range of measurement.…”

“…For instance, PMMA can be used up to the 90 • C at ambient conditions [4,5]. On the other hand, the PC coated temperature sensor could be operated up to 145 • C; however, it shows low sensitivity [28]. By considering all the facts, PS polymer would have been a more appropriate choice for the Fabry-Perot interferometer temperature sensor.…”

“…Various research on the temperature sensors with thermosensitive polymers has been conducted as well. For instance, Rong et al explored the polyvinyl alcohol (PVA) polymer for the application to the Fabry-Perot interferometer sensor [21], Romano et al developed a polydimethylsiloxane (PDMS) coated microfiber mode interferometer sensor [23], Salunkhe et al demonstrated the Fabry-Perot interferometer sensor with polycarbonate (PC) and poly (methyl methacrylate) (PMMA) [28], EI-Amassi et al applied the polystyrene (PS) for the temperature sensor with a photonic crystal fiber [29], and Esposito et al explored the PS coated LPG for temperature sensing [30]. It is acknowledged that the change of the thermal optic coefficient is the prime motive for the temperature-derived index change in the polymer, which plays a crucial role in determining the device performance; thus achieving this feature has been a targeted research goal for optical fiber temperature sensors.…”