Multi-channel fiber-optic temperature sensor system using an optical time-domain reflectometer

Abstract

In this study, we developed a multi-channel fiber-optic temperature sensor system (FTSS) using an optical time-domain reflectometer (OTDR). The developed FTSS consists of fiber-optic temperature-sensing probes, a fiber-optic coupler, a transmitting optical fiber, and an OTDR. The fiber-optic temperature-sensing probes comprise silicon oil, a nickel-plated brass cap, a fiber channel (FC) terminator, and a single-mode optical fiber. The developed FTSS has four channels, which have fiber-optic temperature-sensing probes, connected using single-mode optical fibers of different lengths. Silicon oil is employed as a temperature-sensing material, as its refractive index changes with the temperature variations. We measured the optical powers of the reflected light signals (Fresnel reflection), which are generated at the interface between the silicon oil and core of the single-mode optical fiber in the distal ends of the sensing probes. The optical powers of the four channels of the FTSS were measured to simultaneously determine individual temperatures at four different points using an OTDR. Keywords: Fiber-optic temperature sensor, Optical time-domain reflectometer, Fresnel reflection, Multi-channel