Miniature End-Capped Fiber Sensor for Refractive Index and Temperature Measurement

We have demonstrated an end-of-fiber polydimethylsiloxane (PDMS) cap based fiber Fabry-Pérot interferometer in this letter, which could be used for simultaneous measurement of refractive index (RI) and temperature with extremely low cross sensitivity. The RI and temperature sensitivities of the interferometer are -240.425 dB/RI unit based on extinction ratio measurement in the RI range of 1.3625-1.4150 and 385.46 pm/°C in the temperature range of 25°C-60°C, respectively. Not only does the interferometer have the characteristics of high sensitivity and low cost, but also PDMS has a good biocompatibility, so that the sensor can be used as a cell culture or bacteria growth detection probe.