PDMS-filled Fabry–Perot interferometer-based multipoint temperature measurement using an array-waveguide grating

In this paper, a multipoint temperature measurement scheme based on Fabry–Perot interferometers (FPIs) multiplexing is proposed. The FPI sensor is constructed as a section of hollow-core fiber (HCF) partially filled with polydimethylsiloxane (PDMS) spliced to a single-mode fiber. An array-waveguide grating with 16 channels is used for the FPI sensors’ multiplexing and demultiplexing, and a broadband source is used as the light source. The corresponding theoretical model was built for analysis of the scheme, and the simulation results shown the FPI working principle can be simplified as a dual-beam interference. Two channels connected to two FPI sensors were experimentally tested for the concept verification. The temperature sensitivities of the proposed two sensors are 1.090 dB/°C and 1.210 dB/°C from 30°C to 40°C, respectively. There is no interchannel cross talk observed. Hence, FPI temperature sensors can work simultaneously in this structure, proving the validity of the multipoint temperature measurement concept.