Parallel Double-FPIs Temperature Sensor Based on Suspended-Core Microstructured Optical Fiber

摘要： A configuration based on a parallel double Fabry–Perot interferometers (FPIs) is experimentally demonstrated to enhance temperature sensitivity by Vernier-effect. Two separated FPIs constructed by suspended-core microstructured optical fiber (SCMF) are connected by a 3-dB coupler to form a parallel structure. FPI-2 is used for temperature sensing, while FPI-1 as a reference. With the temperature increasing from 40 oC to 220 oC, both the fine interference fringes and envelope have a linear redshift. This parallel double-FPIs configuration shows an enhanced temperature sensitivity of 153.8 pm/oC with an amplification factor M = 14.6. Moreover, since the free reference FPI-1 is away from the temperature sensing environment, this simple and novel parallel double-FPIs configuration provides good reversibility and stability during the heating and cooling processes.