An In-Situ Electroplating Fabricated Fabry-Perot Interferometric Sensor and Its Temperature Sensing Characteristics

Abstract

In this study, in-situ electroplating method was used to fabricate a metal joint fixed extrinsic Fabry-Perot interferometric (EFPI) sensor. Specifically, optical fibers were firstly chemical plated with a very thin conductive nickel layer and then electroplated with nickel coating. After that, in-situ electroplating method was used to fix the metallized optical fibers and the capillary steel tube, the reflection spectra changes of the EFPI sensors during the in-situ electroplating process were recorded in real time, and the temperature sensing characteristics of the EFPI sensors were studied assisted by the temperature sensing system. Results show that: (i) optical fibers are well protected by the nickel layer; (ii) the reflection spectra of the EFPI sensors are clear and complete in the whole in-situ electroplating process, it is feasible to fabricate a EFPI sensor with the in-situ electroplating method; (iii) with the increases of temperature, the peak numbers of the reflection spectra of the EFPI sensors increase gradually; (iv) the EFPI sensors with different cavity length based on the in-situ electroplating method show excellent sensing characteristics, the temperature sensitivities reach up to about 700, 600, and 400 pm/°C from room temperature to 400 °C, respectively.